Phase-field modeling of microstructure evolution of Cu-rich phase in Fe–Cu–Mn–Ni–Al quinary system coupled with thermodynamic databases
Phase-field modeling of microstructure evolution of Cu-rich phase in Fe–Cu–Mn–Ni–Al quinary system coupled with thermodynamic databases
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DOI：
10.1007/s10853-019-03678-3
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发表时间：
2019-05
影响因子：
4.5
通讯作者：
Yuanyang Sun;Yuhong Zhao;Baojun Zhao;Wenkui Yang;Xiaoling Li;H. Hua
中科院分区：
文献类型：
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作者：
Yuanyang Sun;Yuhong Zhao;Baojun Zhao;Wenkui Yang;Xiaoling Li;H. Hua
扩展和建立了五元相场模型，并结合CALPHAD热力学数据库，成功地研究了Fe-Cu-Mn-Ni-Al五元系热时效过程中扩散控制的相分解和相形态。系统地研究了锰成分对富铜析出物的形态、体积分数、数密度、颗粒大小及长大粗化的影响。模拟结果表明，富铜α相首先形成，Ni、Al、Mn原子向富铜相分配，形成Ni-Al-Mn金属间化合物环/富铜核心相形态，最终由富铜相转变为富铜γ相。体积分数和自由能随模拟时间的变化曲线表明，锰元素可以促进形核驱动力，克服形核初期的障碍，促进富铜相的析出，促进生长和粗化过程。通过数密度(ND)和平均粒度(APS)分析发现，富铜颗粒的数密度(ND)和平均粒度(APS)值随锰含量的增加而增大，表明锰含量越高，越有利于合金的形核和生长。后期沉淀的时间指数分别为0.41、0.42和0.37，与LSW值的0.33有偏差，富铜沉淀的生长和粗化受邻近沉淀的Ostwald熟化和合并粗化的混合机制。这些结果在一定程度上为制备力学性能优良的多元合金钢提供了参考。
Quinary phase-field model was extended and constructed, and the diffusion-controlled phase decomposition and morphology in thermal aging Fe–Cu–Mn–Ni–Al quinary system coupled with CALPHAD thermodynamic databases were successfully studied. The effects of Manganese composition on the morphology, volume fraction, number density, particles size and growth and coarsening of Cu-rich precipitates were investigated systematically. The simulation results showed that Cu-rich α phase was firstly formed, and the Ni, Al and Mn atoms were partitioned to the Cu-rich phase, leading to the formation of a Ni–Al–Mn-rich intermetallic ring/Cu-rich core precipitate morphology and final conversion of Cu-rich phase to Cu-rich γ phase. The curves of volume fraction and free energy variation with simulation time indicated that Mn element can promote nucleation driving force to overcome the nucleation barrier in initial stage and can also accelerate the precipitation of Cu-rich phase and promote the growth and coarsening processes. Through the analysis of number density (ND) and average particle size (APS), we found that the values of ND and APS of Cu-rich particles increase with the rising of Mn content, which indicates that the higher Mn content will boost the nucleation and growth rate. Moreover, the time exponent at the later precipitation was 0.41, 0.42 and 0.37, respectively, which had deviations with the 0.33 of the LSW’s value, and the growth and coarsening of Cu-rich precipitates were under the mixed mechanisms of Ostwald ripening and coalescence coarsening of neighboring precipitates. These results provided useful information for the preparation of multi-component alloyed steel with excellent mechanical properties to some extent.