DEFINE_MATERIAL

This command is for the POLY module.

Read data for a system from a database in the POLY module. It is convenient to use for alloys when there is a major component and the amount of the other elements is known in mass (weight) fraction. The command reads the system from the specified database, sets the composition and temperature (and pressure equal to 1 bar) and calculates the equilibrium state before the prompting for a new command. You can list the results with LIST_EQUILIBRIUM or set a new composition or set axis for a STEP or MAP command.

You cannot append data from different databases in this way. Use this command with data from a USER database.

Syntax	DEFINE_MATERIAL
Prompts	Same elements as before /Y/? This question is asked only if some data is already read from the database, or if the command DEFINE_MATERIAL or DEFINE_DIAGRAM is used. It then offers a convenient way to change the composition and temperature with one command. This command only works properly in cases where the composition of the material system is already defined as in the mole-percent or mass-percent unit.
	Mole percent of <Element> /##/: <Value> or Mass percent of <Element> /##/: <Value> If you have decided to use the same materials system (available in the current POLY3 workspace) by accepting the default (Y) to the previous prompt `Same elements as before /Y/?`, one of the alternative prompts display for each of the components in the defined system, depending on how the composition is defined (either in mole-percent, or in mass-percent). Prompts are repeated until all the defined components are completed. Then, the program prompts to specify the temperature condition.
	Database /ABCDE/: <Database name> The database with the description for the material must be given, or press <Enter> if using the current database. It is possible to give a USER database.
	Major element or alloy: <Element name> The material must have a major element, usually the element which is present in the largest amount. The fraction of this element is not set but is the rest. In some databases there are the alloys predefined. An alloy has a default major element and have limits of the amounts of the alloying elements. If you stay within these limits the calculation gives reasonable results.
	Composition in mass (weight) percent? /Y/: By default the input is taken as mass percent. Choose N to change to mole percent. Composition should be given in PERCENT not FRACTION, as it is required for the `W` and `X` state variables in the SET_CONDITION command.
	1st alloying element: <Element name> The first alloying element must be given. All alloying elements are asked for in a sequence. These can be given in any order. You must know if you are present as assessed systems in the database. There is no error or warning messages if data are missing. Check the documentation of the database selected. If an alloy is selected, a list of legal alloying elements and their maximum percent is listed on-line.
	Mass (weight) percent: <Amount of the above specified element> The amount of the alloying element in mass (weight) percent. Using DEFINE_MATERIAL you cannot use the normal flexibility for conditions, but all must be given in mass percent. However, you can after wards change the conditions using SET_CONDITION.
	2nd alloying element: <Element name> The second alloying element must be given. If only one, press <Enter>. If an element name is given then the program asks for its mass fraction.
	Mass (weight) percent: <Amount of the above specified element> The amount of the above specified alloying element in mass (weight) percent.
	Next alloying element: <Element name> Continue giving elements and mass (weight) fractions until all elements specified. When all alloying elements and their compositions (as in the above prompt) are specified, press <Enter> as answer to this question to finish the materials definition.
	Temperature (C) /1000/: <Temperature of interest in oC> POLY makes the first calculation after retrieving the data for this temperature. By pressing <Enter> to accept the default temperature. The value should be given in Celsius (°C). The pressure is set to 1 bar.
	Reject phase(s) /None/: <List of phase(s) to be rejected> This is a question generated by the database allowing you to select the phases. Normally, all phases should be included when you press <Enter>. If a phase is to be rejected, the name of the phase must be supplied. Several phase names can be specified in one line. It is possible to reject all phase by giving an asterisk . If the number of phases to be included is much smaller than the total number of phases, it may be convenient to first reject all phases and then restore those that should be included. The question is repeated until you press <Enter> after rejecting all unwanted phases or an asterisk .
	Restore phase(s) /None/: <List of phase(s) to be restored> You can restore phases that are accidentally or deliberately rejected. It may also be possible to restore some hidden phases. If phases are to be restored the name of the phases must be supplied. Several phase names can be specified in one line. It is possible to restore all phase by giving an asterisk *. The question is repeated until you press <Enter> after restoring all desired phases.
	OK? /Y/: By default, all phases to be selected from the database have the thermodynamic data retrieved and the references from the chosen database are listed. Enter N if there are any errors or you want to amend the selection then you are returned to the prompt about rejecting phase(s).
	Should any phase have a miscibility gap check? /N/: The database usually creates two or more composition sets for phases that can have miscibility gaps. However, for some phases this is not done automatically, for example the miscibility gap in the bcc phase in Fe-Cr is usually ignored. But if it is important to include a Cr-rich bcc phase, specify this here. It costs some computation time and may make the subsequent MAP or STEP more difficult to converge. If you do not want to have any phase with a miscibility gap in the calculation, press <Enter>. Then, DEFINE_MATERIAL starts calculating the equilibrium, and is terminated.
	To set such a phase with miscibility gaps in the calculation, answer Y. Then the software asks questions about the phase names and their constitutions, such as: Phase with miscibility gap: <Phase name> You must supply the phase name, which has a miscibility gap under the specified system and conditions.
	Major constituent(s) for sublattice #: /AA/: <Constituent(s)> The software shows a default constituent in the sublattice `#(1,2,3,…)`, according to the existing phase definition in the chosen database. You can specify one or more major constituents for the sublattice # in the phase. This question is repeated until all sublattices are specified.
	Phase with miscibility gap: <Phase name> You can supply another phase name with a miscibility gap under the specified system and conditions, and answer the questions concerning the major constituent(s) in associated sublattice(s). By pressing <Enter>, the command starts calculating the equilibrium, and then terminates.
	It is also possible to use this command to select an alloy from a specific database (e.g. the TCNI Ni-based superalloys database). Such alloys are predefined by the OPTION keyword inside the database, and have their default major elements and composition limits of their alloy elements. Such alloys available in the selected database (at the prompt `Database /ABCDE/` can be listed on the screen if typing a ? mark on the prompt `Major element or alloy`. When a specific predefined alloy (instead of a major element) is selected, the major element is staked from the alloy definition and shown on the screen (with a message like `Alloy found with major element NI`). You can only specify alloying elements and the compositions (weight percent or mole percent). Typing a ? at any of the prompts for the alloying element names, e.g. `1st alloying element`, `2nd alloying element`, lists all the alloying elements and the composition limits in the alloy. If the composition of an alloying element is outside of its limit, there is a message (such as `Amount above limit: 30.0000`) and a prompt `Override limit ? /N/`. If you decide to enforce the override by answering `Y` on this prompt (i.e. accepting the over-limit alloying composition), another warning message (such as `Amount of major element below limit: 70.0000`) and prompt `Override limit ? /N/`. Then further decide if enforcing the overriding: if Y then accepting the major element’s composition below the limit; if N then using the predefined major element composition limit.