Ni-Cr-Al合金有序化早期原子尺度的模拟  

Computer Simulation for Ni-Cr-Al Alloy during Early Ordering

作　　者：褚忠[1] 陈铮[1] 王永欣[1] 卢艳丽[1] 李永胜[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《稀有金属材料与工程》2006年第2期242-246,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金资助(50071046)

摘　　要：基于三元体系的离散格点的微观相场模型,模拟研究温度1123K时三元合金Ni-Cr-Al有序化早期过程,通过研究沉淀过程原子图像和序参数曲线的演化,发现低饱和度合金Ni-15at.%Cr-10.5at.%Al沉淀机制为非经典形核长大,沉淀过程包括D022有序相的形核长大,L12有序相的形核和D022有序相向L12有序相的转化3个阶段。由于Cr原子替代Al原子位置,在L12有序相内两种原子占位几率接近,形成Ni3(CrxAl1-x)结构的L12有序相,并且与D022有序相共存。高饱和度合金沉淀机制为等成分有序化和失稳分解混合机制,并且有序化和簇聚过程比低饱和度合金提前。The aging behavior of Ni-Cr-Al ternary alloy are studied at temperature 1123 K, the early ordering process are simulated at atomic-scale with microscopic phase-field model. Precipitation mechanism of low supersaturated alloy Ni-15at.%Cr-10.5at.%Al is non-classical nucleation and growth, the precipitation process include three stages, i.e. the nucleation and growth of D022 ordering phase, nucleation of l2 ordering phase and transmit of Ll2 ordering phase from D022 ordering phase. The occupation possibilities of AI and Cr in Ll2 ordering phase are similar because of substitution behavior of Cr atom, Ni3（CrxAl1-x） structure are formed and coexist with D022 ordering phase, high supersaturated alloys show the congruent ordering and spinodal decomposition mechanism and the process of the ordering and clustering are precedent to low supersaturated alloys.

关 键 词：微观相场模型 Ni—Cr-Al 沉淀 计算机模拟 

分 类 号：TG111[金属学及工艺—物理冶金]