SET_ALL_START_VALUES

This command is available for the POLY and ED-EXP modules.

Set start values, e.g. if the calculation fails or if you have a miscibility gap or ordering. If temperature and pressure are not conditions, you are asked for values of them. Then for each phase prompt on if it should be stable and on its constitution.

Syntax

set_all_start_values

 

T /XXXX/: <Temperature in K>

If the temperature is not a condition, supply a guess of its final value (in K).

 

P /100000/: <Pressure in Pa>

If the pressure is not a condition supply a guess of its final value (in Pa).

Prompts

Automatic start values for phase constitutions? /N/: <Y, N or F>

  • For N, enter an initial amount of each entered phase and the major constituents or site fraction of each constituent.
  • For Y, the program automatically sets the start values for phase constitutions in all possible phases.
  • F is for force. In some cases the calculation fails because impossible conditions are set, e.g. W(C)=1.5 [W(C) is mass fraction and must thus be less than unity. The program tries to fulfill this condition by putting maximum amount of carbon in all phases, but can fail anyway. When you detect the error and set W(C) to 0.015, the calculation may still fail because it could start from the previous values. To get back to ‘fresh’ start values, choose F.
 

Should <phase> be stable /N/: <Y/1 or N/2>

A guess if this phase should be stable or not is requested. All entered phases are prompted for this question and next two.

You cannot have more phases stable than you have components, but at least one (which dissolves all constituents) must be set as stable. For backward compatibility, this question can be answered by 1 (for Yes) or 0 (for No).

The phase name may have a hash sign # followed by a digit, e.g. BCC_A2#2. For phases with miscibility gaps, there should be two phases with the same name but with different numbers after the hash sign.

 

Major constituent(s): <Name of major constituent(s) in the phase>

The constituent with the largest fraction in the phase should be specified. If there are more than one constituent with a large fraction, give them all on the same line. If the default major constituents should be used answer with an asterisk (*). By giving $ the constitution is not changed. If there should be no major constituent give NONE and or if the major constituent(s) are improperly specified, you are asked for individual fractions in the phase.

 

Y(<phase>,<constituent>) /.XXXXXXXXXX/: <.YYYYY>

The current value (.XXXXXXXXXX) is default. You can accept the default by pressing <Enter> or give a new value (.YYYYY).

The phase name or constituent name may have a hash sign # followed by a digit, e.g. Y(BCC_A2#2,FE), Y(BCC_A2#2,C#2). For phases with miscibility gaps, there should be two phases with the same name but with different numbers after the hash sign. For phases with sublattices, the constituents in sublattice 2 or higher is also be suffixed with a hash sign # followed by a digit.