Ni-Al-V合金DO_(22)相间有序畴界面的微观相场模拟

Simulation of Ordered Domain Interfaces Formed between DO_(22) Phases in Ni-Al-V Alloy Using Microscopic Phase-Field Model

利用微观相场动力学模型模拟Ni-Al-V合金沉淀过程中DO22(Ni3V)相沿[100]和[001]方向形成的有序畴界面,对界面结构及其界面处合金元素的成分进行了研究。结果表明:DO22相沿[100]和[001]方向形成3种稳定界面,且都不可以迁移;界面性质与界面结构有关,(002)//(100)界面处易析出L12相,主要存在于沉淀早期;(002)//(100)·?[100]界面在沉淀后期易形成一种过渡界面;{110}孪晶界面则是三类界面中相对常见和稳定的界面;合金元素在不同的界面处有不同的偏聚和贫化倾向,在所有的界面处V原子贫化而Ni原子偏聚,Al原子在(002)//(100)·?[100]界面处贫化,在其它界面处偏聚,且各元素在不同的界面处偏聚以及贫化程度也不一样。

Microscopic phase-field model was used to simulate the ordered domain interfaces formed between DO22 （Ni3V） phases along [100] and [001] direction in Ni-Al-V alloy. The atomic structure of the interface and the composition of alloying elements at the interfaces were investigated using the occupation probability of atoms. The results show that there are three kinds of stable interfaces formed between DO22 phases （Ni3V） along [100] and [001] direction, and all of them can not migrate. The property of interfaces is related to the atomic structure of interfaces. The L 12 phases are precipitated at the （002）//（100） interfaces easily, and this kind of interfaces mainly exist at the early period of precipitation, the （002）//（100）1/2[100] interface can form a kind of transitional interface at the early period of precipitation, while the { 110} twin interface is the most stable and usual interface of the three kinds of interfaces. The elements of alloy have different preferences of segregation and depletion at different boundaries, V is depleted but Ni is segregated at all interfaces; Al is depleted at the （002）//（100）1/2[1100] interface but segregated at the other interfaces. The degrees of segregation and depletion are different at different interfaces.