examples.rar_合金_合金枝晶_多相场_枝晶_高温合金

This is document provides a desription of the HexDendr examples of OpenPhase (www.openphase.de). This example is dedicated to simulations of Mg-Al alloy solidification. The relevant parameters of the alloy are set in the /ProjectInput/DiffusionInput.opi file. The entries of the linearized phase diagramm are given by $Ts_(AB) and $Cs_(AB) which indicate the points of intersection of the solidus/liquidus/solubility lines for a pair of phases (Ts - is the temperature while Cs is corresponding composition). The first index (A) is always indicating the phase with which given line of the phase diagramm is in direct contact, while the second index (B) is indicating a complimentary phase which form a dual phase region with phase (A). Parameters ML_(AB) and ML_(BA) set the corresponding solidus/liquidus/solubility lines slopes. The slopes in contact with the stoichimetric phase lines are set to "0.0" ("inf" is not a good input value). A phase can be marked as stoichiometric (no diffusion, no solubility, fixed concentration) using the parameters $Flag_(A). Value "0" is used for nonstoichiometric phases and any nonzero value can be used for stoichiometric ones. In this example the phase with index (0) coreesponds to the Mg-Al melt, while index (1) corresponds to the HCP Mg-Al phase and index (2) denotes the beta Mg-Al phase. The respective initial phase concentrations are set by the parameters $C0_(A), where (A) is again a phase index. Parameters $CMIN and $CMAX are used for numerical bounds of the phase concentrations. They can be any physically correct value between 0 and 100 %. Narrower intervals are some times preferred when for example a phase does not exist outside of certain concentration range. The temperature dependent diffusion coefficients D_(A) for a phase (A) are set by a pair of DC_(A) (diffusion coefficient) and AE_(A) (activation energy) parameters of the Arhenius formula: D_(A) = DC_(A) * Exp[-AE_(A)/(R*T)], where R is a gas constant. If activation energy is set to 0.0 the diffusion coefficient becomes temperature independent: D_(A) = DC_(A). Parameters relevant for temperature settings are $R0(X,Y,Z) which set the starting point of the applied temperatre gradient in the simulation box. The starting temperature value $T provided in the /ProjectInput/ProjectInput.opi file is set as the starting value at the point $R0(X,Y,Z) and then the temperature gradient given by the parameters $DT_DR(X,Y,Z) is applied starting from this value/point. The cooling/heating rate $DT_Dt is applied in all simulation points equally in each time step, providing the temperature change by $DT_Dt * $dt value. The time step value $dt is given in the /ProjectInput/ProjectInput.opi file.