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Introduction to ACCESS

Examples

This page provides a guided introduction to the operation of ACCESS by reference to the retrieval of data for various types of system. Examples of the commands are given in an red. Examples of output are provided.

The first three sections cover the essential aspects of ACCESS; Later sections deal with more specialised features and the final section with problem handling. The user will not need to have a full knowledge of all these features immediately. On the other hand it will be worth reading about them so that the information can readily be found when needed, especially because decisions made in data retrieval can affect the results of calculations and the ease of obtaining them.

For the most part the same considerations apply to the retrieval of data from within MULTIPHASE and the other calculation modules. However, ACCESS gives greater control particularly with regard to changing the priority of data from different databases and dealing with missing data.

Any reference to database names does not imply that these will be available to individual users. Users can, in any case, set up mtconfig.txt files to assign aliases to any databases used.

Retrieving and inspection of a simple system from a database

The commands in ACCESS are

    DEFINE    LIST    CLASSIFY     SAVE      RETURN

The function of these will be described by reference to the system C-H-O.

define system "C,H,O" source demo_a output "cho" !

DEFINE SYSTEM is used to name the components of the system. They are entered, delimited by commas, as a list in quotes. The data are to be retrieved from the DEMO_A database.

It is good practice to begin by naming the datafile in which the retrieved data are to be stored. The data filenames have the extension .mpi so that, in this example, the file name will be "cho.mpi". The root name should preferably be short to allow space for the identification by number of results files from the calculation modules, eg a graph file produced by MULTIPHASE using cho.mpi as the datafile might be called cho127.gph

The report of this search is obtained using the command LIST.

list system components !

The LIST SYSTEM keywords produce a display, in this case of the components in the system, together with other information. The status of the components cannot be changed within ACCESS.

list system phases substances !

Retrieval of data for substances (edited table of output)

ACCESS OPTION ?  list system phases substances !
 NUMBER    PHASE                   STATUS      MODEL
   1       GRAPHITE                NORMAL      PURE SUBSTANCE
   2       DIAMOND                 absent      PURE SUBSTANCE
   3       GAS                     NORMAL      IDEAL GAS
   4       CH4O                    absent      PURE SUBSTANCE
   5       H2O                     absent      PURE SUBSTANCE

 NUMBER    UNARY/SUBSTANCE         STATUS                  SOURCE
   1       C<GRAPHITE>             NORMAL                  DEMO_A
   2       C<DIAMOND>              NORMAL                  DEMO_A
   5       C3<g>                   absent                  DEMO_A
  11       CH4<g>                  NORMAL                  DEMO_A
  13       C2H2<g>                 NORMAL                  DEMO_A
  15       C2H4<g>                 NORMAL                  DEMO_A
  17       C2H6<g>                 NORMAL                  DEMO_A
  18       C3H4_1<g>               absent                  DEMO_A
  19       C3H4_2<g>               absent                  DEMO_A
  26       CH4O                    absent                  DEMO_A
  27       CH4O<g>                 absent                  DEMO_A
  29       CO<g>                   NORMAL                  DEMO_A
  30       CO2<g>                  NORMAL                  DEMO_A
  34       H2<g>                   NORMAL                  DEMO_A
  35       HO<g>                   absent                  DEMO_A
  37       H2O                     NORMAL                  DEMO_A
  38       H2O<g>                  NORMAL                  DEMO_A
  39       H2O2<g>                 absent                  DEMO_A
  40       O<g>                    absent                  DEMO_A
  41       O2<g>                   NORMAL                  DEMO_A
  42       O3<g>                   absent                  DEMO_A

The lists of phases and substances that result from this command would be similar to that given in the table, except that the status column has already been modified as demonstrated below by the CLASSIFY command. Many substances have also been edited out altogether. In referring to phases when using CLASSIFY it is important to use the numbers or unique abbreviations of the names given in these lists. All condensed substances are assigned to different phases unless their phase labels are identical (see General Introduction to MTDATA). All gases join the same phase. Substances 18 and 19 are gaseous isomers.

The CLASSIFY command allows the status of phases and substances to be changed. Specifically, when multiple databases are being used, CLASSIFY is used to revoke the precedence of the first-retrieved data set for a given substance. Substances may be referred to in a number of different ways. It is however most straightforward to refer to them as SUBSTANCE(s) where s refers to a single, group or range of substances expressed by number or by a unique abbreviation of the formula as shown using the LIST command. Phases should be specified using PHASE(p) where p refers to phases in an analogous way.

If all calculations are to be made at high temperatures and moderate pressures, it is useful to delete volatile phases and diamond.

classify absent p(dia,H2O,CH4O) !    or
classify absent p(2,4,5) !

The same effect could have been achieved by using the substances corresponding to these phases by the command classify absent s(2,26,37) !.  This method is much less convenient for solution phases.

If desirable to save computing time or for other reasons, substances can be deleted from within a phase as follows.

classify absent s(3-10,12,14,16,18-28,35,36,39,40,42) !

It is possible to omit the "s" for substance eg: classify absent 3 4 5 6 ... !. However, in this method the substance numbers cannot be grouped by means of hyphens, so it is often less efficient. It is sometimes convenient to begin with a clean slate by removing all substances and/or phases and bringing back those of interest. This is done by entering "*" or "all" to represent all integers for example: 

classify absent s(*) p(*) normal p(1,3) s(1,11,13 etc) ! 

save

The SAVE command has no arguments. When it is entered:

-    if the status of a phase is ABSENT, none of the substances in that phase are saved, even when their status is NORMAL;
-    equally if all the substances within a phase have an ABSENT status, the phase is not saved, even if its status is NORMAL.

The command SAVE completes the preparation of a datafile having the extension .mpi. Note that the root name of the output file has to be defined before the data are saved. If this is not done the data will be saved to the default file, "def.mpi", which can, however, be renamed by invoking an operating system command, eg: "$ren def.mpi mf7a.mpi".

Only one SAVE per system definition is effective. In order to prepare a modified datafile for the same system it must be redefined from scratch.

Hint: Up-arrow keys can be used to recover previous commands in some operating systems and versions of MTDATA. Otherwise, the log file generated during the first attempted retrieve can be edited and used as a macro for the purpose of repeating a long sequence of commands.

Solution data (elemental components)

With the exception of gases and ideal aqueous solutions, data for solution phases comprise unary data for the end members (and sometimes associates) together with data for binary and sometimes ternary interactions. If a binary interaction is ideal a zero should be explicit in the database. Interactions of order higher than 3 are rare. For crystalline substances, solution is considered to occur by substitution on lattice sites. In many cases there are two or more sublattices, which in general do not have equal numbers of sites. Interstitial sites are treated as forming a separate sublattice, mostly populated by vacancies. This is why the fcc phase has two sublattices in the below table. Sublattices are also used in the ionic liquid model but with variable site ratios.

The interaction or the unary data can be tagged in the database as potentially a source of immiscibility, in which case the status of phases including such data will be listed as "1 M G". The user can override these settings, as in the following command which cancels a hypothetical miscibility gap in the liquid phase and introduces one for the bcc phase.

class misc(liq) none misc(bcc) 1 !

The name given to a phase is an important item of data and must be consistent; all the data for the phase must bear the same name. The sublattice ratios are included in the phase name so the full name for the fcc phase is exactly FCC_A1:1:1 which, however, can be abbreviated in ACCESS.

The example concerns the system Fe-Cr-Ni, the data for which are assumed to come from a hypothetical database called DEMO_B. If the data are to be used for the calculation of TERNARY phase diagrams the order of the components is significant. The output mpi file is named as stl.mpi.

def sys "Fe,Cr,Ni" source none_but demo_b output "stl" !

In this command none_but is used to ensure that previous database lists are not searched.

Retrieval of data for the Fe,Cr,Ni system

ACCESS OPTION ? list sys phas subs !
 NUMBER    PHASE                   STATUS      MODEL
   1       LIQUID                  NORMAL      PURE SUBSTANCE
   2       SIGMA:8:4:18            NORMAL      PURE SUBSTANCE
   3       BCC_A2:1:3              1  M-G      PURE SUBSTANCE
   4       FCC_A1:1:1              NORMAL      PURE SUBSTANCE

 NUMBER    UNARY/SUBSTANCE         STATUS                  SOURCE
   1       Cr<LIQUID>              NORMAL                  DEMO_B
   2       Fe:Cr:Cr<SIGMA>         NORMAL                  DEMO_B
   3       Fe:Cr:Fe<SIGMA>         NORMAL                  DEMO_B
   4       Fe:Cr:Ni<SIGMA>         NORMAL                  DEMO_B
   5       Ni:Cr:Cr<SIGMA>         NORMAL                  DEMO_B
   6       Ni:Cr:Fe<SIGMA>         NORMAL                  DEMO_B
   7       Ni:Cr:Ni<SIGMA>         NORMAL                  DEMO_B
   8       Cr<BCC_A2>              NORMAL                  DEMO_B
   9       Cr<FCC_A1>              NORMAL                  DEMO_B
  10       Fe<LIQUID>              NORMAL                  DEMO_B
  11       Fe<BCC_A2>              NORMAL                  DEMO_B
  12       Fe<FCC_A1>              NORMAL                  DEMO_B
  13       Ni<LIQUID>              NORMAL                  DEMO_B
  14       Ni<BCC_A2>              NORMAL                  DEMO_B
  15       Ni<FCC_A1>              NORMAL                  DEMO_B

ACCESS OPTION ? save

SIMPLIFIED MODEL USED FOR PHASE BCC_A2:1:3
SIMPLIFIED MODEL USED FOR PHASE FCC_A1:1:1


Note that the order of search is alphabetic with respect to the elements within each phase but the order of phases depends on the order in which they are found.

Depending on the intended application the list of phases and substances may include redundant phases or substances, for example the gas and liquid. If so they can be classified absent.

save

When the data are saved the models are automatically simplified for any sublattice phases for which there is mixing on only one sublattice and a message is output to the screen to that effect.

The use of multiple databases.

The number of immediately available databases and their names or aliases corresponds with the entries in the mtconfig.txt file. A list of the available databases can be found by entering a question as follows.

def source ?

In the following example the databases DEMO_A and CVD are chosen.

def out "iphb" sys "In,P,H,Br" source demo_a cvd !
list system phases sub !

By default, substances that are duplicated in different databases will be classified as normal for the first database searched and absent for any subsequent database in the list. For this reason the databases should normally be entered in order of expected value to the problem. If the user had specially prepared the CVD database for a particular problem then it would be appropriate to place it before DEMO_A in the database list.

Once the desired status has been achieved for all phases and substances it is necessary to save the data..

save

Hints: In the use of data from databases of different origins it is important to avoid saving data for the same substance under different aliases. For example the same substance might be called Fe2O3<FE2O3>, Fe2O3<ALPHA>, Fe2O3<HAEMATITE>, Fe2O3<HEMATITE> or more logically Fe2O3<CORUNDUM> since corundum is the generic name for the phase.

On no account should the same name be used for two different phases, as it will result in the two phases being treated as a single solution phase for which interaction data will be required. For this reason names such as "BETA" should be avoided.

It is also desirable to avoid saving data for substances that differ only slightly in their composition but are in fact the same phase. For example Pr6O11 and PrO1.833 would probably be different representations of the same substance.

When switching priority for a substance to a second database it is necessary to make the second occurrence normal after making the first absent.

It is useful to arrange for the list of substances to go to a local printer for purposes of checking and subsequent monitoring of how the results were achieved.


Systems of non-elemental and charged components

For a number of reasons it is useful to be able to set up datafiles for systems in terms of non-elemental components and these are considered individually below.

Restriction of systems to subsystems

The chemical reactions in a system may be limited in such a way that the effective number of components is less than the number of elements. For example, the reaction of ammonia with hydrogen chloride at low temperatures does not produce nitrogen, hydrogen or chlorine at a significant rate, so "NH3,HCl" is a better description of the system than "N,H,Cl" for these conditions.

ACCESS operates by retrieving the names of all substances including solution species corresponding to the elemental system and then eliminating those that are not within the possibly more restricted system defined by the non-elemental components. This provides the user with the opportunity to see the names of the eliminated substances and to make a judgement about the validity of the current choice of components. The substances that cannot be formed from a linear combination of the defined components are given the "EX-SYSTEM" status. This status must not be changed if errors are to be avoided.

The use of dummy elements to represent metastable molecules is considered later.

Choosing components to match experiment

Even though a choice of components other than the elements normally has no effect on the operation of MULTIPHASE and other calculation modules, there are circumstances under which it may be beneficial. The objective in seeking the best choice of components should be to imitate experiment as far as possible, defining the system in terms of independent rather than dependent variables. As a simple example, water (gaseous or liquid) is the dominant product of the H-O system. At low temperatures especially, the amount of molecular hydrogen and oxygen coexisting with water in a mixture of exact composition H2O is immeasurably small, possibly less than one molecule in one mole of water, and an exact mass balance at these low levels cannot be attained. Problems in calculating equilibria in such systems can in most cases be overcome by defining the system as "H2O,O" or "H2O,H" rather than as "H,O". If the system is defined as "H2O,H", negative amounts of H imply an excess of O over that required to make H2O.

Choosing components for convenience in stepping

For convenience in stepping compositions along a particular direction in the system it may be useful to choose one of the components to correspond with this direction. For example if it were desired to calculate the effect of adding methane to a system, the component list could include CH4 and H rather than C and H. (MULTIPHASE does offer another method of achieving a similar result, namely the setting of named start and finish compositions.)

Reference states and component Selection

In MULTIPHASE it can be useful to represent a component such as oxygen (for which the monatomic form is not the reference state) as the dimer, O2, when the data are retrieved. If this is done and the gas is made the reference phase for oxygen in MULTIPHASE, then calculated thermodynamic functions will have values that are in line with standard tabulations.

Electronic charge as a component

Although it is possible for calculations to be made in systems open to electronic charge, particularly commonly in COPLOT, this is rarely useful in MULTIPHASE. The amount of charge in a closed system and indeed any phase within the system must be zero, and therefore the electron is not formally a component of the system overall. Nevertheless, either the electron or another charged species must be declared in the list of components to allow the formation of ionic species to be quantified. In versions of MTDATA later than 5.0 this is carried out automatically as long as the appropriate configuration variable is set. The same applies when charged species are used to model the thermodynamic properties of other types of phase, notably ionic solids and melts. If the charged component is made the last in the system list, ACCESS organises it as a constraint on the system that fixes the amount of charge in the system and in each phase to be zero, as in the following example.

def sys "CaO,FeO,Fe2O3,Al2O3,SiO2,O/-2" source oxdemo !

The inclusion of both FeO and Fe2O3 in the system definition effectively makes oxygen a component. As a result data will be retrieved not only for unaries (charged or uncharged) that lie within the space limited by the components but also for any of the metallic elements and oxygen itself.

If it is desired to make a charged species an explicit component in the calculation modules (ie one for which the amount can be set), it should be included early in the component list. Two charged components should not be included in the same system definition. ACCESS permits charge to be an explicit component only for systems including aqueous or gaseous phases. The following examples show the definition of an iron-water system in different ways. In each case four components are defined and an identical set of species retrieved from the databases. However, in the first two of the examples at least one charged species is included early (ie not last) in the list. Only in these two cases will the components in the resultant datafile be such as to allow the amount of charge to be fixed or free to vary from zero in the calculation modules. Whereas, in the third and fourth examples, it will not be possible to specify the amount of charge, since this is constrained to zero.

def sys "Fe,H/+,H2,H2O" source aqex hot !
def sys "Fe,/-,O2,H2O" !

def sys "Fe,H,O,/-" !
def sys "Fe3O4,H2O,H2,H/+" !

list sys sub !

Aqueous systems

clas absent p(H2O) ! save

If the aqueous phase is present, water with the phase label H2O must be made absent, leaving data for H2O<aq>. The AQEXTRAS database includes data for the conventional (ie not real) aqueous electron. Unless calculations are to be made using COPLOT it is preferable to classify / <aq> as absent in ACCESS before saving the data to a datafile.

If calculations require a charged species to be an explicit component in an aqueous phase, it is essential that all charged gaseous species are made absent. The reason for this is that MTDATA currently has no knowledge of electric potential. Hence, if charge is an explicit component it would be redistributed between aqueous and gaseous phases unless the above precaution were taken.

Isotopes

The data retrieval system and calculation modules in principle allow isotopes to be considered. The main current limitation is that none appears in the look-up table of atomic weights that is incorporated into MTDATA and therefore no calculations can be made involving mass fractions. Moreover, no data are provided for isotopic species in the SGTE databases. Hence users wishing to work with isotopes will have to provide their own data. It should be noted that incorporating data for all but rare isotopes will upset the data for more abundant species. Perhaps the worst case is that of lithium for which the thermodynamic properties of 6Li and 7Li are significantly different and the abundances are comparable. In such a case it would be desirable to introduce data for two or more distinct new elements, for example Lj and Lk, and to omit the data for Li. The reader should note that the provision of thermodynamic data for individual isotopic species is not as straightforward as it might seem, as it is necessary to decouple the data for the individual isotopes from the previously assessed data for the mixture.

Dummy elements representing molecules

There are many examples in chemistry in which molecular groups are stable in practice though not at true equilibrium. For example, during the formation of complexes in aqueous systems a complexing agent such as ethylenediamine cannot be in full equilibrium with the system. For such a case it would be possible to generate data for a minimal neutral form of the complexing agent, assigning it a two letter symbol as though it were an element. Data could then be introduced into a database for the complexing agent and its compounds with the elements or ions. ACCESS would allow the retrieval of these data in the normal way but, as at present with isotopes, it would not be possible to undertake calculations involving mass.

Using this method of providing molecules with aliases it is possible and entirely justifiable for a system to contain more components than elements.

Choosing a component order for TERNARY

The TERNARY module allows the arrangement of the components around the triangular phase diagram to be changed. However, the need for the change can be avoided by appropriate selection of the order when defining the components of the system. In TERNARY the default sequence puts the first component at bottom left and orders the other components clockwise.

define system "CaCl2,KCl,ZnCl2" source salts0 output "s37a" !

In this case the model used has taken no account of charge, whereas it is normal to employ a model that recognises the existence of charged entities in the liquid and solid solutions. The particular system discussed below, namely NaCl-NaI-KCl-KI, appears to have four components. However, these are linearly related by the chemical equation:

    NaCl + KI = NaI + KCl

which reduces the number of components necessary to define the overall system to three. The system is said to be reciprocal.  Charge is used to model the properties of one of the phases and this requires the addition of one of the ionic species to the list of components raising the total once more to four. Note that it would be incorrect to replace Cl/- by /-, since no combination of the components would then generate the charged ions. The charged component must be the last in the list so that it is not treated as a formal component but as a constraint on the system.

define system "NaCl,KCl,NaI,Cl/-" source salts1 !

On reciprocal plots the first pair of components (taken in the sequence 1,2,3,1) having a common first element will be assigned to the top left and top right of the diagram. In the above example, because the third and first components both contain Na as the first element, they will occupy respectively the upper left and upper right corners of the diagram.

Hints for dealing with large systems

By default the maximum number of components that can be handled by MTDATA is 30. For systems involving several elements that form many compounds together, there is a possibility that a search of multiple databases will retrieve more than the upper limit of substances for the ACCESS module. This is more likely for versions that have been deliberately configured for small systems.

In such a case, if a search of the individual databases reveals that most of the data can be found in one of the databases eg SGTE but a few substances must be retrieved from other databases, it is possible that a very large overlap will cause the maximum number of species to be exceeded. If so the following procedure can be followed. Use the UTILITY module to create a temporary database and include it in your database list in the mtconfig.txt file. Save the additional data into the temporary file by means of the THERMOTAB module. Once this is done go back to ACCESS and do a search of SGTE and the temporary database only.

If necessary, MTDATA can be reconfigured for more substances or indeed for less.

Model simplification

When mixing occurs only on one of the sublattices of a phase with more than one sublattice and this sublattice has a site ratio of unity, the default option is to simplify the data as though there was no sublattice structure. This speeds up calculations. However, if desired the full model can be retained by changing an MTDATA configuration variable, either interactively or in the mtsignon.txt file, by entry of [SUBLATTICE=NOCHANGE. By entry of [SUBLATTICE=SIMPLIFY the default can be restored.

Implicit component

At the request of a user an MTDATA configuration variable has been added to allow a named component to be added automatically to all systems defined whilst the variable is given a value other than NONE. For example the entry [IMPLICIT_COMPONENT=O/-2, either interactively or in the active mtsignon.txt file would add "O/-2" at the end of any defined system name. It is recommended that an implicit component is declared only in an mtsignon.txt file in a work area used exclusively in connection with appropriate systems.

Problems caused by missing data

The way the ACCESS module works when data are missing can be modified by the user's setting of an MTDATA configuration variable MISSING_DATA. This has the default setting of FAIL, which can be changed, either semi-permanently in the mtsignon.txt file or, temporarily at the ACCESS prompt, by entry of [MISSING_DATA=CONTINUE. The value can be restored to FAIL in the same manner.

The example given in the following tables was obtained using the system Fe-Cr-Ni-C, which is of major importance in steels. The action required by the user would depend very much on the application. For example data for the liquid would not be needed unless the steel were to be melted. The general principles will be considered before the details of the example. In the following description any reference to MULTIPHASE should be taken to imply any of the equivalent calculation modules within MTDATA.

Binary interactions

If datasets for two unaries are found for a given phase, ACCESS expects to find data relating to their interaction in solution in that phase. If no interaction data are present when the command save is entered, what happens depends on the status of the configuration variable MISSING_DATA. If MISSING_DATA=FAIL, data equivalent to ideal interaction (excess Gibbs energy = 0) will be inserted in the saved mpi file but the data will be preceded by an error flag (a line containing the word "REMOVE") that will cause the reading of the mpi file by the calculation modules to be aborted and an error message sent to the screen. The error flag will be omitted if MISSING_DATA=CONTINUE and the .mpi file will load into MULTIPHASE with the problem phases classified as absent.

In either case a warning message is given that a file misbin.dbl has been generated containing zero interaction data sets for the solutions lacking interaction data. These data can be compiled using the UTILITY module into a separate database or, if the original database were "owned" by the user, the misbin.dbl file could be appended to the data loading file (extension name .loa or .dbl) and the whole recompiled. The retrieval of the data could then be repeated. 

An alternative but strongly deprecated method is to use a text editor (not a word processor) to search for and delete the lines containing "REMOVE" that prevent the .mpi file being used. In the nature of things the phases for which data are missing are likely to be the less common phases. In the example shown in the next table many datasets for binary interactions are indicated as missing. These datasets will not be needed for systems if elements that stabilise the phase are absent. For such systems the best procedure may be to classify the phase as absent. This is a significant step which should be a conscious decision of the MTDATA user. It is for this reason that the option of manually omitting the phase or automatically including ideal data have been made user choices rather than the default. The setting of the MISSING_DATA variable forms part of the user's options.

Unary data

Unary data may also be missing, more probably for  sublattice than simple phases. If unaries are missing, error messages will be sent to the screen when the data are saved, listing which datasets are missing. The best procedure to adopt is first to check whether the phase or phases in question may be unstable. If the phase is not needed, the retrieval process should be repeated as before but the phase should be classified as absent before the save command is issued. It is possible that ACCESS has inferred the need for the missing unary from the presence of another in a sublattice phase. In such cases omission of that unary may allow the save to proceed smoothly.

If the phase is considered unlikely to form or the component is considered unlikely to dissolve in the phase but there is a degree of uncertainty, the simplest option is to set the MISSING_DATA configuration variable to CONTINUE. When the data are saved a value of zero will be assigned to the unary and the status of the phase will be absent when the data are read by MULTIPHASE.

If on the other hand the phase is potentially important to the system and the component likely to dissolve in it, the user should create or add to his own data loading file and insert data for the missing unaries using a text editor. The format for such data should be as specified in the UTILITY handbook or as output by THERMOTAB when data are listed. The misbin.dbl file created during the save operation will provide an excellent foundation for adding "real" data. The UTILITY module should then be used to compile the load file into a database (eg mydata.dbs/inx) and to include this database in the current list specified in the mtconfig.txt file. The data retrieval process using ACCESS can then be repeated with the mydata database specified before other databases. See the hints given in relation to missing binary data. The UTILITY manual should be consulted on the procedure for database creation.

Magnetic data

ACCESS decides whether a phase requires magnetic data on the basis of the existence or absence of magnetic data for the first unary retrieved for the phase. If no magnetic data flag is present for that unary, ACCESS will omit any magnetic data found for the other unaries and warnings to this effect will be given.

If magnetic data are present for other unaries the user should create or add to his own data loading file the existing data for the first unary with explicit magnetic data appended even if the values are zero. The THERMOTAB module can be used to generate a file containing the existing data which can be edited to include magnetic data, normally an explicit zero. This file can then be used as a data loading file or it can be appended to an existing data loading file. The procedure described above for handling missing unary data can then be followed.

Mixed models

For the present at least ACCESS will not save files containing data for phases containing substances represented by more than one temperature expression, eg G-Hser and Cp formats. If for example one retrieves data for a system from UNARY (G-Hser format) and SGSUB (Cp format), any data for gaseous species from UNARY must be classified as absent and the data for the same species in the SGSUB classified normal before the data are saved (This will not apply if you are using the G-Hser version of the SGSUB database). Care should also be taken not to mix incompatible data for the unaries and interactions in solution phases.

Reference states must also be consistent. The data for unaries in the SGTE databases are referred to the elements at 298.15 K. They should not be mixed with what are known as lattice stability data, for which the reference is an arbitrary phase at current temperature.

 
Example for the Fe-Cr-Ni-C system

The first table below shows a list of the phases for which at least some datasets were present in sgsol version 3.01. At this stage an entry of NORMAL in the STATUS column does not guarantee that the data for the phase are complete. Moreover, the entries in the MODEL column do not fully distinguish different types of substance. The MODEL column is updated after the data are saved. The phase type is given more completely later which shows the status of data retrieved by MULTIPHASE after incomplete datasets were saved.

The list of unaries is given in the following table. A metallurgist looking at the list of phases would notice immediately a number of unexpected phases and others that were rather unlikely to form. Some of these phases could certainly be classified as absent at this stage. However, for illustrative purposes, all the data in the example are saved so that the diagnostics can be explained. Note that MISSING_DATA has been set to CONTINUE.

Data retrieval for the Fe,Cr,Ni,C system (list of phases)

ACCESS OPTION ? [MISSING_DATA=CONTINUE
ACCESS OPTION ? define sys "Fe,Cr,Ni,C" source sgsol out "st1b" !

SEARCHING FOR SYSTEM Fe,Cr,Ni,C
sgsol         - SGTE Solution Database 3.01 - 19/7/93

ACCESS OPTION ? list system phases !

 NUMBER    PHASE                   STATUS      MODEL
   1       DIAMOND_A4              NORMAL      PURE SUBSTANCE
   2       GRAPHITE                NORMAL      PURE SUBSTANCE
   3       LIQUID                  NORMAL      PURE SUBSTANCE
   4       GAS                     NORMAL      IDEAL GAS
   5       BCC_A2:1:3              NORMAL      PURE SUBSTANCE
   6       CEMENTITE:3:1           NORMAL      PURE SUBSTANCE
   7       FCC_A1:1:1              NORMAL      PURE SUBSTANCE
   8       HCP_A3:1:.5             NORMAL      PURE SUBSTANCE
   9       KSI_CARBIDE:3:1         NORMAL      PURE SUBSTANCE
  10       M3C2:3:2                NORMAL      PURE SUBSTANCE
  11       M7C3:7:3                NORMAL      PURE SUBSTANCE
  12       M23C6:20:3:6            NORMAL      PURE SUBSTANCE
  13       CBCC_A12:1:1            NORMAL      PURE SUBSTANCE
  14       CUB_A13:1:1             NORMAL      PURE SUBSTANCE
  15       FE4N:4:1                NORMAL      PURE SUBSTANCE
  16       FECN_CHI:2.2:1          NORMAL      PURE SUBSTANCE
  17       M5C2:5:2                NORMAL      PURE SUBSTANCE
  18       V3C2:3:2                NORMAL      PURE SUBSTANCE
  19       CR3SI:3:1               NORMAL      PURE SUBSTANCE
  20       CRSI2:1:2               NORMAL      PURE SUBSTANCE
  21       CHI_A12:24:10:24        NORMAL      PURE SUBSTANCE
  22       SIGMA:8:4:18            NORMAL      PURE SUBSTANCE
  23       AL5FE4                  NORMAL      PURE SUBSTANCE
  24       AL3NI2:.6:.4            NORMAL      PURE SUBSTANCE
  25       ALNI_B2:.5:.5           NORMAL      PURE SUBSTANCE


The list of diagnostic messages, at first, looks rather daunting but in fact only a few factors are causing all the messages. Problems not revealed by the diagnostics (eg for the M3C2 and M7C3 phases) are potentially equally important and will be considered later. The first seven lines merely show that a sublattice model for a phase has been simplified because there was solution on at most one of the sublattices. The important information summarised at the foot of the table refers to five phases. Of these the HCP phase occurs in alloys based on other elements eg Ti and for modelling specific carbide phases. For this system the phase can be ignored. The CBCC_A12 and CUB_A13 phases are found in manganese rich alloys. These phases can therefore safely be removed from the system. The two remaining problems concern CEMENTITE and M23C6 which need further consideration.

List of substances retrieved for the Fe,Cr,Ni,C system

ACCESS OPTION ? list system subs !
 NUMBER    UNARY/SUBSTANCE         STATUS                  SOURCE
   1       C<DIAMOND_A4>           NORMAL                  SGSOL
   2       C<GRAPHITE>             NORMAL                  SGSOL
   3       C<LIQUID>               NORMAL                  SGSOL
   4       C<g>                    NORMAL                  SGSOL
   5       C2<g>                   NORMAL                  SGSOL
   6       C3<g>                   NORMAL                  SGSOL
   7       C4<g>                   NORMAL                  SGSOL
   8       C5<g>                   NORMAL                  SGSOL
   9       C6<g>                   NORMAL                  SGSOL
  10       C7<g>                   NORMAL                  SGSOL
  11       Cr:C<BCC_A2>            NORMAL                  SGSOL
  12       Cr:C<CEMENTITE>         NORMAL                  SGSOL
  13       Cr:C<FCC_A1>            NORMAL                  SGSOL
  14       Cr:C<HCP_A3>            NORMAL                  SGSOL
  15       Cr:C<KSI_CARBIDE>       NORMAL                  SGSOL
  16       Cr:C<M3C2>              NORMAL                  SGSOL
  17       Cr:C<M7C3>              NORMAL                  SGSOL
  18       Cr:Cr:C<M23C6>          NORMAL                  SGSOL
  19       Fe:Cr:C<M23C6>          NORMAL                  SGSOL
  20       Cr:Fe:C<M23C6>          NORMAL                  SGSOL
  21       Fe:C<BCC_A2>            NORMAL                  SGSOL
  22       Fe:C<CBCC_A12>          NORMAL                  SGSOL
  23       Fe:C<CEMENTITE>         NORMAL                  SGSOL
  24       Fe:C<CUB_A13>           NORMAL                  SGSOL
  25       Fe:C<FCC_A1>            NORMAL                  SGSOL
  26       Fe:C<FE4N>              NORMAL                  SGSOL
  27       Fe:C<FECN_CHI>          NORMAL                  SGSOL
  28       Fe:C<HCP_A3>            NORMAL                  SGSOL
  29       Fe:C<KSI_CARBIDE>       NORMAL                  SGSOL
  30       Fe:C<M5C2>              NORMAL                  SGSOL
  31       Fe:C<M7C3>              NORMAL                  SGSOL
  32       Fe:C<V3C2>              NORMAL                  SGSOL
  33       Fe:Fe:C<M23C6>          NORMAL                  SGSOL
  34       Ni:C<BCC_A2>            NORMAL                  SGSOL
  35       Ni:C<CEMENTITE>         NORMAL                  SGSOL
  36       Ni:C<FCC_A1>            NORMAL                  SGSOL
  37       Ni:C<HCP_A3>            NORMAL                  SGSOL
  38       Ni:Ni:C<M23C6>          NORMAL                  SGSOL
  39       Cr<LIQUID>              NORMAL                  SGSOL
  40       Cr<g>                   NORMAL                  SGSOL
  41       Cr:Cr<CR3SI>            NORMAL                  SGSOL
  42       Cr:Cr<CRSI2>            NORMAL                  SGSOL
  43       Cr:Cr:Cr<CHI_A12>       NORMAL                  SGSOL
  44       Fe:Cr:Fe<CHI_A12>       NORMAL                  SGSOL
  45       Fe:Cr:Fe<SIGMA>         NORMAL                  SGSOL
  46       Fe:Cr:Cr<CHI_A12>       NORMAL                  SGSOL
  47       Fe:Cr:Cr<SIGMA>         NORMAL                  SGSOL
  48       Cr:Cr:Fe<CHI_A12>       NORMAL                  SGSOL
  49       Ni:Cr:Fe<SIGMA>         NORMAL                  SGSOL
  50       Fe:Cr:Ni<SIGMA>         NORMAL                  SGSOL
  51       Ni:Cr:Ni<SIGMA>         NORMAL                  SGSOL
  52       Ni:Cr:Cr<SIGMA>         NORMAL                  SGSOL
  53       Cr:Va<BCC_A2>           NORMAL                  SGSOL
  54       Cr:Va<CBCC_A12>         NORMAL                  SGSOL
  55       Cr:Va<CUB_A13>          NORMAL                  SGSOL
  56       Cr:Va<FCC_A1>           NORMAL                  SGSOL
  57       Cr:Va<HCP_A3>           NORMAL                  SGSOL
  58       Fe<AL5FE4>              NORMAL                  SGSOL
  59       Fe<LIQUID>              NORMAL                  SGSOL
  60       Fe<g>                   NORMAL                  SGSOL
  61       Fe:Va<BCC_A2>           NORMAL                  SGSOL
  62       Fe:Va<CBCC_A12>         NORMAL                  SGSOL
  63       Fe:Va<CUB_A13>          NORMAL                  SGSOL
  64       Fe:Va<FCC_A1>           NORMAL                  SGSOL
  65       Fe:Va<HCP_A3>           NORMAL                  SGSOL
  66       Ni<LIQUID>              NORMAL                  SGSOL
  67       Ni:Ni<AL3NI2>           NORMAL                  SGSOL
  68       Ni:Ni<ALNI_B2>          NORMAL                  SGSOL
  69       Va:Ni<ALNI_B2>          NORMAL                  SGSOL
  70       Ni:Va<BCC_A2>           NORMAL                  SGSOL
  71       Ni:Va<CBCC_A12>         NORMAL                  SGSOL
  72       Ni:Va<CUB_A13>          NORMAL                  SGSOL
  73       Ni:Va<FCC_A1>           NORMAL                  SGSOL
  74       Ni:Va<HCP_A3>           NORMAL                  SGSOL
 NORMAL SUBSTANCE COUNT =   74

Messages sent to screen after saving the data without reclassification

ACCESS OPTION ?  save
 SIMPLIFIED MODEL USED FOR PHASE M3C2:3:2
 SIMPLIFIED MODEL USED FOR PHASE FE4N:4:1
 SIMPLIFIED MODEL USED FOR PHASE FECN_CHI:2.2:1
 SIMPLIFIED MODEL USED FOR PHASE M5C2:5:2
 SIMPLIFIED MODEL USED FOR PHASE V3C2:3:2
 SIMPLIFIED MODEL USED FOR PHASE CR3SI:3:1
 SIMPLIFIED MODEL USED FOR PHASE CRSI2:1:2
 SIMPLIFIED MODEL USED FOR PHASE AL3NI2:.6:.4
 ERROR: NO DATA FOR BINARY INTERACTION Cr,Ni:C<CEMENTITE:3:1>
 ERROR: NO DATA FOR BINARY INTERACTION Cr,Ni:C<HCP_A3:1:.5>
 ERROR: NO DATA FOR BINARY INTERACTION Cr,Ni:Va<HCP_A3:1:.5>
 ERROR: NO DATA FOUND FOR UNARY Cr:Ni:C<M23C6>
 ERROR: NO DATA FOUND FOR UNARY Fe:Ni:C<M23C6>
 ERROR: NO DATA FOUND FOR UNARY Ni:Cr:C<M23C6>
 ERROR: NO DATA FOUND FOR UNARY Ni:Fe:C<M23C6>
 ERROR: NO DATA FOR BINARY INTERACTION Cr:Cr,Ni:C<M23C6:20:3:6>
 ERROR: NO DATA FOR BINARY INTERACTION Cr,Ni:Cr:C<M23C6:20:3:6>
 ERROR: NO DATA FOR BINARY INTERACTION Cr:Fe,Ni:C<M23C6:20:3:6>
 ERROR: NO DATA FOR BINARY INTERACTION Cr,Ni:Fe:C<M23C6:20:3:6>
 ERROR: NO DATA FOR BINARY INTERACTION Cr,Fe:Ni:C<M23C6:20:3:6>
 ERROR: NO DATA FOR BINARY INTERACTION Cr,Ni:Ni:C<M23C6:20:3:6>
 ERROR: NO DATA FOR BINARY INTERACTION Fe:Cr,Ni:C<M23C6:20:3:6>
 ERROR: NO DATA FOR BINARY INTERACTION Fe,Ni:Cr:C<M23C6:20:3:6>
 ERROR: NO DATA FOR BINARY INTERACTION Fe:Fe,Ni:C<M23C6:20:3:6>
 ERROR: NO DATA FOR BINARY INTERACTION Fe,Ni:Fe:C<M23C6:20:3:6>
 ERROR: NO DATA FOR BINARY INTERACTION Fe,Ni:Ni:C<M23C6:20:3:6>
 ERROR: NO DATA FOR BINARY INTERACTION Ni:Cr,Fe:C<M23C6:20:3:6>
 ERROR: NO DATA FOR BINARY INTERACTION Ni:Cr,Ni:C<M23C6:20:3:6>
 ERROR: NO DATA FOR BINARY INTERACTION Ni:Fe,Ni:C<M23C6:20:3:6>
 ERROR: NO DATA FOUND FOR UNARY Cr:C<CBCC_A12>
 ERROR: NO DATA FOUND FOR UNARY Ni:C<CBCC_A12>
 ERROR: NO DATA FOR BINARY INTERACTION Cr:C,Va<CBCC_A12:1:1>
 ERROR: NO DATA FOR BINARY INTERACTION Cr,Fe:C<CBCC_A12:1:1>
 ERROR: NO DATA FOR BINARY INTERACTION Cr,Ni:C<CBCC_A12:1:1>
 ERROR: NO DATA FOR BINARY INTERACTION Cr,Fe:Va<CBCC_A12:1:1>
 ERROR: NO DATA FOR BINARY INTERACTION Cr,Ni:Va<CBCC_A12:1:1>
 ERROR: NO DATA FOR BINARY INTERACTION Fe,Ni:C<CBCC_A12:1:1>
 ERROR: NO DATA FOR BINARY INTERACTION Fe,Ni:Va<CBCC_A12:1:1>
 ERROR: NO DATA FOR BINARY INTERACTION Ni:C,Va<CBCC_A12:1:1>
 ERROR: NO DATA FOUND FOR UNARY Cr:C<CUB_A13>
 ERROR: NO DATA FOUND FOR UNARY Ni:C<CUB_A13>
 ERROR: NO DATA FOR BINARY INTERACTION Cr:C,Va<CUB_A13:1:1>
 ERROR: NO DATA FOR BINARY INTERACTION Cr,Fe:C<CUB_A13:1:1>
 ERROR: NO DATA FOR BINARY INTERACTION Cr,Ni:C<CUB_A13:1:1>
 ERROR: NO DATA FOR BINARY INTERACTION Cr,Fe:Va<CUB_A13:1:1>
 ERROR: NO DATA FOR BINARY INTERACTION Fe,Ni:C<CUB_A13:1:1>
 ERROR: NO DATA FOR BINARY INTERACTION Cr,Fe:C<CUB_A13:1:1>
 ERROR: NO DATA FOR BINARY INTERACTION Ni:C,Va<CUB_A13:1:1>

 ******    5 PHASES IDENTIFIED WITH INCORRECT OR MISSING DATA ******
 PHASE: CEMENTITE:3:1
 ERROR: Missing data for binary interaction(s)
 PHASE: HCP_A3:1:.5
 ERROR: Missing data for binary interaction(s)
 PHASE: M23C6:20:3:6
 ERROR: Missing data for unary(s)
 PHASE: CBCC_A12:1:1
 ERROR: Missing data for unary(s)
 PHASE: CUB_A13:1:1
 ERROR: Missing data for unary(s)
 ****** GOOD DATAFILE CREATED (but missing/inconsistent data) ******
            ****************************************************
            * FOR MISSING INTERACTION DATA SEE FILE misbin.dbl *
            ****************************************************


CEMENTITE, M3C, is unlikely to form in steels that are rich in Cr because the M23C6, M7C3 and M3C2 phases will form in preference. However, CEMENTITE is more likely to form in high carbon alloys that are poor in Cr and other elements that are strong carbide formers. The problem with the data lies with the missing dataset for the binary interaction between Cr and Ni on the first sublattice. This is written Cr,Ni:C<CEMENTITE:3:1>. The best course for the moment is to allow data for the phase to be saved with a zero for the excess Gibbs energy for this interaction. If the phase is reclassified as NORMAL after the data are recovered by MULTIPHASE and it is found that both Cr and Ni are concentrated in the phase, then critically assessed data should be sought to replace the zero. In fact the data are readily available and are now included in the current version of SGSOL.

Recovery by MULTIPHASE of the data saved in table 2.8.2

ACCESS OPTION ? ret multiphase
MULTIPHASE OPTION ? define data "st1a" !
 Date and time of run  5 JAN 94  14:47:49
 * DATAFILE = st1a.mpi    CREATED 14:46 05/01/94
 * SYSTEM = Fe,Cr,Ni,C,
 * NUMBER OF PHASES  =  25
 * NUMBER OF SPECIES =  80
 *
                         ********************************
                         * UNASSESSED OR INCORRECT DATA *
                         ********************************
                      *************************************
                      * WARNING/ERRORS HAVE BEEN DETECTED *
                      *************************************

   2 Errors(s)  : UNASSESSED DATA    Missing data for binary(s)
   3 Errors(s)  : UNASSESSED DATA    Missing data for unary(s)

MULTIPHASE OPTION ? list sys phas !

 NUMBER    PHASE                   STATUS      MODEL
   1       DIAMOND_A4              NORMAL      PURE SUBSTANCE
   2       GRAPHITE                NORMAL      PURE SUBSTANCE
   3       LIQUID                  NORMAL      REDLICH KISTER
   4       GAS                     NORMAL      IDEAL GAS
   5       BCC_A2                  NORMAL      SUBLATTICE
   6       CEMENTITE               absent      SUBLATTICE
   7       FCC_A1                  NORMAL      SUBLATTICE
   8       HCP_A3                  absent      SUBLATTICE
   9       KSI_CARBIDE             NORMAL      SUBLATTICE
  10       M3C2                    NORMAL      PURE SUBSTANCE
  11       M7C3                    NORMAL      SUBLATTICE
  12       M23C6                   absent      SUBLATTICE
  13       CBCC_A12                absent      SUBLATTICE
  14       CUB_A13                 absent      SUBLATTICE
  15       FE4N                    NORMAL      PURE SUBSTANCE
  16       FECN_CHI                NORMAL      PURE SUBSTANCE
  17       M5C2                    NORMAL      PURE SUBSTANCE
  18       V3C2                    NORMAL      PURE SUBSTANCE
  19       CR3SI                   NORMAL      PURE SUBSTANCE
  20       CRSI2                   NORMAL      PURE SUBSTANCE
  21       CHI_A12                 NORMAL      SUBLATTICE
  22       SIGMA                   NORMAL      SUBLATTICE
  23       AL5FE4                  NORMAL      PURE SUBSTANCE
  24       AL3NI2                  NORMAL      PURE SUBSTANCE
  25       ALNI_B2                 NORMAL      SUBLATTICE


The remaining problem concerns the M23C6 phase. All the missing unaries and binary interactions referred to in the diagnostics are implied by the existence of a dataset for the unary Ni:Ni:C<M23C6:20:3:6>, which is number 38 in the list of unaries given in the table. Nickel is not an important contributor to M23C6 and for this reason it would be reasonable to delete the unary, hence avoiding the problem.

In principle, similar questions arise concerning the M3C2 and M7C3 phases. Inspection of the table shows that only one unary is present for M3C2, namely number 16, Cr3C2. The user should consider whether Fe and conceivably Ni might dissolve in this phase, in which case data would be needed for the two unaries and the three binary interactions. The data for the M7C3 phase include two unaries, namely Cr7C3 and Fe7C3 and the interaction between them. There are no datasets relating to solution of Ni in this phase but this is certainly less important and the extent of solution may be negligible.

If the possible problem of the M3C2 phase is ignored, the steps needed to eliminate the difficulties are illustrated in the table, in which all phases unlikely to contribute are classified as absent as well as the Ni:Ni:C unary in the M23C6 phase. A list of phases and a small section of the substance list is given in the Table. The list of phases has been annotated with "-" and "?" respectively to indicate phases that are rather obviously not required and those which are known not be relevant through knowledge of the data or the physical metallurgy.

Reclassification of phases and a unary in the Fe,Cr,Ni,C system

ACCESS OPTION ? [MISSING_DATA=CONTINUE
ACCESS OPTION ? def sys "Fe,Cr,Ni,C" out "st1b" !

SEARCHING FOR SYSTEM Fe,Cr,Ni,C
sgsol         - SGTE Solution Database 3.01 - 19/7/93

ACCESS OPTION ? classify absent phases(1,4,8,9,13-21,23-25) sub(38) !
ACCESS OPTION ? list system phases !

 NUMBER    PHASE                   STATUS      MODEL
   1       DIAMOND_A4              ABSENT      PURE SUBSTANCE
   2       GRAPHITE                NORMAL      PURE SUBSTANCE
   3       LIQUID                  NORMAL      PURE SUBSTANCE
   4       GAS                     ABSENT      IDEAL GAS
   5       BCC_A2:1:3              NORMAL      PURE SUBSTANCE
   6       CEMENTITE:3:1           NORMAL      PURE SUBSTANCE
   7       FCC_A1:1:1              NORMAL      PURE SUBSTANCE
   8       HCP_A3:1:.5          ?  ABSENT      PURE SUBSTANCE
   9       KSI_CARBIDE:3:1      ?  ABSENT      PURE SUBSTANCE
  10       M3C2:3:2                NORMAL      PURE SUBSTANCE
  11       M7C3:7:3                NORMAL      PURE SUBSTANCE
  12       M23C6:20:3:6            NORMAL      PURE SUBSTANCE
  13       CBCC_A12:1:1         ?  ABSENT      PURE SUBSTANCE
  14       CUB_A13:1:1          ?  ABSENT      PURE SUBSTANCE
  15       FE4N:4:1             ?  ABSENT      PURE SUBSTANCE
  16       FECN_CHI:2.2:1       ?  ABSENT      PURE SUBSTANCE
  17       M5C2:5:2                ABSENT      PURE SUBSTANCE
  18       V3C2:3:2                ABSENT      PURE SUBSTANCE
  19       CR3SI:3:1               ABSENT      PURE SUBSTANCE
  20       CRSI2:1:2               ABSENT      PURE SUBSTANCE
  21       CHI_A12:24:10:24     ?  ABSENT      PURE SUBSTANCE
  22       SIGMA:8:4:18            NORMAL      PURE SUBSTANCE
  23       AL5FE4                  ABSENT      PURE SUBSTANCE
  24       AL3NI2:.6:.4            ABSENT      PURE SUBSTANCE
  25       ALNI_B2:.5:.5           ABSENT      PURE SUBSTANCE

ACCESS OPTION ? list sys subs !

    note that the list has been shortened

 NUMBER    UNARY/SUBSTANCE         STATUS                  SOURCE
  36       Ni:C<FCC_A1>            NORMAL                  SGSOL
  37       Ni:C<HCP_A3>            NORMAL                  SGSOL
  38       Ni:Ni:C<M23C6>          ABSENT                  SGSOL
  39       Cr<LIQUID>              NORMAL                  SGSOL
  40       Cr<g>                   NORMAL                  SGSOL


The diagnostics resulting from saving the data are given at the head of the table. As expected only one problem remains, namely the missing data for the interaction between Cr and Ni in CEMENTITE. The remainder of the Table shows the result of recovering the data into MULTIPHASE. Note that CEMENTITE is classified as absent. This should be reclassified as NORMAL before calculations are undertaken. The user should take steps to obtain good data for the interaction of Cr and Ni as soon as possible.

Results of pruning the phase and unary list before saving

ACCESS OPTION ? save
 SIMPLIFIED MODEL USED FOR PHASE M3C2:3:2
 ERROR: NO DATA FOR BINARY INTERACTION Cr,Ni:C<CEMENTITE:3:1>
 ******    1 PHASES IDENTIFIED WITH INCORRECT OR MISSING DATA ******
 PHASE: CEMENTITE:3:1
 ERROR: Missing data for binary interaction(s)
 ****** GOOD DATAFILE CREATED (but missing/inconsistent data) ******
            ****************************************************
            * FOR MISSING INTERACTION DATA SEE FILE misbin.dbl *
            ****************************************************
ACCESS OPTION ? ret multiphase 
MULTIPHASE OPTION ? define data "def" !
 Date and time of run  6 JAN 94  12:08:46
 * DATAFILE = def.mpi    CREATED 12:08 06/01/94
 * SYSTEM = Fe,Cr,Ni,C,
 * NUMBER OF PHASES  =   9
 * NUMBER OF SPECIES =  34
 *
                         ********************************
                         * UNASSESSED OR INCORRECT DATA *
                         ********************************
                      *************************************
                      * WARNING/ERRORS HAVE BEEN DETECTED *
                      *************************************

   1 Errors(s)  : UNASSESSED DATA    Missing data for binary(s)

MULTIPHASE OPTION ? lis sys phases !

 NUMBER    PHASE                   STATUS      MODEL
   1       GRAPHITE                NORMAL      PURE SUBSTANCE
   2       LIQUID                  NORMAL      REDLICH KISTER
   3       BCC_A2                  NORMAL      SUBLATTICE
   4       CEMENTITE               absent      SUBLATTICE
   5       FCC_A1                  NORMAL      SUBLATTICE
   6       M3C2                    NORMAL      PURE SUBSTANCE
   7       M7C3                    NORMAL      SUBLATTICE
   8       M23C6                   NORMAL      SUBLATTICE
   9       SIGMA                   NORMAL      SUBLATTICE

MULTIPHASE OPTION ? lis sys subs !

 NUMBER    SUBSTANCE               STATUS/CONSTRAINT       SOURCE
   1       C<GRAPHITE>             NORMAL                  SGSOL
   2       C<LIQUID>               NORMAL                  SGSOL
   3       Cr<LIQUID>              NORMAL                  SGSOL
   4       Fe<LIQUID>              NORMAL                  SGSOL
   5       Ni<LIQUID>              NORMAL                  SGSOL
   6       Cr:1<BCC_A2>            NORMAL                  SGSOL
   7       Fe:1<BCC_A2>            NORMAL                  SGSOL
   8       Ni:1<BCC_A2>            NORMAL                  SGSOL
   9       C:2<BCC_A2>             NORMAL                  SGSOL
  10       Va:2<BCC_A2>            NORMAL                  SGSOL
  11       Cr:1<CEMENTITE>         NORMAL                  SGSOL
  12       Fe:1<CEMENTITE>         NORMAL                  SGSOL
  13       Ni:1<CEMENTITE>         NORMAL                  SGSOL
  14       C:2<CEMENTITE>          NORMAL                  SGSOL
  15       Cr:1<FCC_A1>            NORMAL                  SGSOL
  16       Fe:1<FCC_A1>            NORMAL                  SGSOL
  17       Ni:1<FCC_A1>            NORMAL                  SGSOL
  18       C:2<FCC_A1>             NORMAL                  SGSOL
  19       Va:2<FCC_A1>            NORMAL                  SGSOL
  20       Cr3C2<M3C2>             NORMAL                  SGSOL
  21       Cr:1<M7C3>              NORMAL                  SGSOL
  22       Fe:1<M7C3>              NORMAL                  SGSOL
  23       C:2<M7C3>               NORMAL                  SGSOL
  24       Cr:1<M23C6>             NORMAL                  SGSOL
  25       Fe:1<M23C6>             NORMAL                  SGSOL
  26       Cr:2<M23C6>             NORMAL                  SGSOL
  27       Fe:2<M23C6>             NORMAL                  SGSOL
  28       C:3<M23C6>              NORMAL                  SGSOL
  29       Fe:1<SIGMA>             NORMAL                  SGSOL
  30       Ni:1<SIGMA>             NORMAL                  SGSOL
  31       Cr:2<SIGMA>             NORMAL                  SGSOL
  32       Cr:3<SIGMA>             NORMAL                  SGSOL
  33       Fe:3<SIGMA>             NORMAL                  SGSOL
  34       Ni:3<SIGMA>             NORMAL                  SGSOL

   
It is instructive to examine the entries in the list of substances at the foot of the table (after retrieval by MULTIPHASE) and to compare them with the entries in an earlier table (before saving by ACCESS). The substances in this table are in fact species on the individual sublattices rather than unaries. For example unary Ni:Cr:Fe<sigma> contributes to the three species  Ni:1, Cr:2 and Fe:3, where the number indicates the sublattice. Conversely species Ni:1 receives contributions from unaries Ni:Cr:Fe<SIGMA>, Ni:Cr:Ni<SIGMA> and Ni:Cr:Cr<SIGMA>.

Updated 25 May 2010