Mn含量对Fe-Cu-Mn-Ni合金中富Cu相析出影响的相场法研究

Study on Effect of Mn Content on Cu-Rich Phase Precipitates in Fe-Cu-Mn-Ni Alloy by Phase Field Method

通过耦合CALPHAD热力学数据库建立了一个模拟多元合金固态相变过程中微观组织演变的相场模型,并以Fe-Cu-Mn-Ni合金为例,从动力学角度揭示了Mn含量对富Cu相析出机制的影响。结果表明:随着富Cu相的析出,Mn和Ni原子在富Cu相的中心发生偏聚,导致在富Cu相界面形成B2环。Mn含量变化会改变富Cu相的形貌和析出机制。在Mn含量较低时,富Cu相仅发生Ostwald粗化,其形貌为球形;而在Mn含量较高时,富Cu相的粗化机制包括Ostwald粗化和合并长大,其形貌从球形转变为棒状。提高Mn含量会促进富Cu相的析出,其体积分数和半径也增大,但数量减少。

A phase-field model for simulating the microstructure evolution during the solidstate phase transformation of multi-component alloys was established by coupling the CALPHAD thermodynamic database.Taking Fe-Cu-Mn-Ni alloy as an example,the effect of Mn contents on the precipitation mechanism of Cu-rich phase was revealed in terms of the kinetics.The research results showed that with the precipitation of the Cu-rich phase,Mn and Ni atoms segregated in the center of the Cu-rich phase,resulting in the formation of a B2 ring at the interface of Cu-rich phase.The variation in Mn composition resulted in the change of the morphology and precipitation mechanism of the Cu-rich phase.When the Mn content was low,the Cu-rich phase only generated Ostwald coarsening,and its morphology was spherical;when the Mn content was high,the coarsening mechanism of Cu-rich phase included Ostwald coarsening and coalescence,and its morphology changed from spherical to rod-like.The increase in the Mn content can promote the precipitation of Cu-rich phase,and an increase in volume fraction and radius,but a decrease in its number.