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基于微观相场模型,研究Ni75Al4.2V20.8相变过程中Ni3V-DO22相中合金元素占位几率演化规律与Ni3Al-L12相长大之间的内在关联。结果表明L12相长大过程可以分为两个阶段。在前期,DO22相内合金元素的成分基本保持不变;在后期,DO22相中Ni和Al的浓度降低,而V的浓度升高。合金元素在DO22相中各个格点位置上的浓度发生不同变化;为L12相长大后期提供部分合金元素:其中,Ni主要来源于DO22相中的V格点位置;Al主要来源于NiI和V格点位置;由于DO22相体积减少而富余的V向DO22相内部扩散,主要占据V和NiII格点位置。L12相长大的后期主要受DO22相内反位缺陷和第三组元的演化所控制。
Based on the microscopic phase field model, the relationship between the evolution of the occupancy probability of alloying elements in Ni3V-DO22 phase and the growth of Ni3Al-L12 phase in Ni75Al4.2V20.8 phase transformation was studied. The results show that L12 phase growth process can be divided into two stages. In the early stage, the composition of the alloying elements in DO22 phase remained basically unchanged. In the later stage, the concentrations of Ni and Al in DO22 phase decreased while the concentrations of V increased. The concentrations of alloying elements changed at different lattice sites in DO22 phase, and some alloying elements were provided for the late L12 phase. Ni mainly came from the V lattice sites in DO22 phase. Al mainly came from NiI and V Lattice position; due to the reduction of the volume of DO22 phase and the V-to-DO22 phase of the internal proliferation, mainly occupy V and NiII lattice position. The later period of L12 facies growth is mainly controlled by the inversion faults in DO22 facies and the evolution of the third component.