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Let us imagine you want to know what are the equilibrium phases in a Fe-Cr-Ni-C system which composition would be 18/12/0.05, Fe being the balance to 100.
|You type (+enter)||The prompt is||Comments|
|WHICH MODULE ?|
|multiphase||MULTIPHASE OPTION ?||You entered the multiphase
module (more about modules)
|define||DEFINE WHAT ?||You can have a look a all the possibilities by typing simply ?|
|source||ENTER LIST OF DATABASE NAMES :||The same ? will give you the list of sources you can use (more about databases).|
|plus !||MULTIPHASE ?||The ! marks the end of the command ( more about general command structure).|
Now you can define the system in a similar way:
define system 'Fe,Cr,Ni,C' !
MTDATA goes through the different databases you selected and keeps all the phases which can be formed by the elements you gave. Because the variable [MISSING_DATA is set to CONTINUE, MT_DATA will not stop if parameters are missing, but you will find the phase initially classified as ABSENT.
Because there are not too many phases in this example, you can use them all:
classify normal p(*) !
set w 100 !
Now, defining the amount of each component :
set w( )
Note that you need to leave a space between the two
parentheses. This will cause mtdata to ask you the amount of each
component. Since you don't want to bother calculating what is the
amount of Fe in the system, just enter undef when it asks you
about the mass of Fe. It will calculate the amount of Fe to balance.
Once you've finished (ie you've entered the amount of C), you see the prompt DEFINE WHAT ? This is because you didn't type the ! which will cause mtdata to execute the command you just entered.
Is just left the temperature:
set temperature 973 !and everything is ready for mtdata to perform (more about set).
compute print brief print mole !
which gives you the amount and the composition of each phase present.
If you want all the possible results (gibbs energy of individual phases, mole and weight distribution tables..) type:
compute print each_stage_result !
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