of liquidus contours and primary phase fields for a multicomponent
application is used for the calculation of liquidus contours and
primary phase fields for a triangular cut in composition through the
phase diagram of a multicomponent, multiphase system (contours
generated from calculated liquidus temperatures for
compositions defined on a triangular grid).
forms of output can be obtained depending on the options requested. For
example in addition to carrying out the
calculations, the application will replot previously calculated
diagrams eg liquidus temperature points, jagged and smoothed liquidus
temperature contours, liquidus primary phase names or numbers at grid
points and jagged and smoothed liquidus primary phase boundaries. This
application can also be used to produce a solidus surface.
asking for the liquidus contours and primary phase fields to be
calculated it is necessary to define a
datafile for the multicomponent system (for three or more components),
to classify any phases required to be absent or identified as
giving rise to miscibility gaps and to specify the pressure. All this
can be set up using the normal APPLICATION commands within MTDATA.
Also it is necessary to define the range of temperatures to be covered
by the scan for the liquidus valleys
range t 500 1200 0.1 !
third value here represents the tolerance in temperature ie the
accuracy required for each calculation of
the liquidus temperature. A value of 0.1 will achieve a high degree of
accuracy, although calculations might be
a little slow. On the other hand a value of 10 might be suitable for
obtaining a rough quick view of the
application is designed for a multicomponent system (ie with at least
three components). The following example, however, is for a three
component system. In this case the ternary section is identical to a
the liquidus projection for an ordinary ternary diagram. To calculate
sections in higher order systems it is necessary simply
to add more components to the composition groups.
set 'A' 0.9998 0.0001 0.0001 !
'B' 0.0001 0.9998 0.0001 !
'C' 0.0001 0.0001 0.9998 !
density of calculations is set through use of the user variable
"number_of_steps" (maximum of 100).
the corners of the diagram assigned to the composition groups.
user_v(group_top) 'B' !
user_v(group_lower_right) 'C' !
is also necessary to specify how the diagram should be labelled. Two
different options are available The default
option (0) is for the temperatures to be printed out at point on the
triangular grid on the "jagged"
temperature plot. Alternatively the phase field names or numbers may be
given (option 1). eg:
is initiated by entering the compute command.
options are also available when displaying the results of the
calculation. Potting option 0
(the default) is required for the calculation to be carried out and
this dispays the full set of
graphical output. Results are then stored in a
".liq" file. The other plotting options provide the
means to plot some or all of the graphs from results stored in the
".liq" file. eg.
set user_v(plotting_option) 3
options 3 and 4 provide the full range of graphs as is displayed
immediately following the calculation.
With plotting option 4, however, the labelling of the smoothed primary
phase boundaries is suppressed. Plotting options 0 to 4 all provide a
plot of the temperature or primary phase number at each grid point
depending on the value set for the labelling_option. Option 1 also
provides a plot of the "jagged" temperature contours over the array of
grid points and a plot of the smoothed, labelled, temperature contours.
Option 2, on the
other hand, provides a plot of the "jagged" primary phase boundaries
over the array of grid points and a plot
of the smoothed, named primary phase fields. Plotting options 5 and 6
provide a highly restricted selection of output. Option 5 provides a
plot of the smoothed, labelled, temperature contours while option 6
provides a plot
of the smoothed, named primary phase fields.
refinement to the calculations is possible by using the user variable
"defn_method". By default the value of "defn_method" is set to 0 and
the calculations proceed assuming that it is
the boundary at the highest temperature that is required. However if
"defn_method" is 1 then the user
is asked to define whether a LIQUIDUS or SOLIDUS surface is required
and then to categorise
each phase according to whether it should be treated as a liquid or as
a solid or to be ignored with respect to finding a phase boundary.
"defn_method" is 2, further refinement is possible:
set user_v(defn_Method) = 2 !
user variables, Liq_Solidus, liq_phs_nos and ign_phs_nos provide the
user variable Liq_Solidus allows a resticted set of the available lines
to be calculated and plotted, liq_phs_nos allow a particular phase (or
phases) to be assigned as the liquid phase and ign_phs_nos allows
certain phases to ignored in terms of the definition of the phase
boundaries although still present in the calculations.
the liquidus curve is calculated defined as the highest temperature at
which a solid is still present or at which a liquid miscibility gap is
1 just the liquidus curve is required
defined as the highest temperature at which a solid is still present
2 just the solidus curve is required
defined as the highest temperature at which no liquid is present.
3 all boundaries are required except those
corresponding to those phases that are to be ignored, defined by the
user variable ign_phs_nos
user variables liq_phs_nos and ign_phs_nos should be entered within
quotes. If a list of numbers is
given they be separated by + signs. Multiple numbers for liq_phs_nos
both liquid and gas phases to be assigned as high temperature phases eg
results from a LIQSECT calculation may be displayed as a three
dimensional image using the LIQSURF
projections may also be calculated using other MTDATA applications ie. LIQPROJ and LIQCONT. They
use different ways to delineate the liquidus valley. LIQCONT may give
better temperature contours than LIQSECT while
LIQCONT may give better indication of the primary phase boundaries for
the liquidus but take longer. LIQPROJ is limited to ternary systems.