Ni-Cr-Al合金中D0_(22)相和L1_2相沉淀过程微观相场模拟  

Microscopic Phase-Field Simulation for the Precipitation Process of D0_(22) and L1_2 Phases in Ni-Cr-Al Alloy

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

机构地区：[1]西北工业大学,陕西西安710072

出　　处：《稀有金属材料与工程》2007年第12期2099-2103,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金资助项目(50071046);国家"863"资助项目(2002AA331051)

摘　　要：基于微观相场动力学模型和微观弹性理论,对Ni75Cr19Al6.0合金的沉淀过程进行了研究。结果表明,合金沉淀初期,D022相以失稳分解机制从无序基体中析出,L12相以非经典形核长大机制析出,两相均呈现不规则形状且随机分布。共格沉淀相和母相之间的点阵错配度引起的弹性场对沉淀过程产生明显影响,D022相和L12相在沉淀后期表现出强烈的各向异性特征,其形貌均转变为长方块状,沿弹性"软"方向([100]和[001])规则分布,沉淀后期在基体中形成高度择优取向的微观组织。粗化过程中,D022相和L12相的平均半径的立方与时效时间整体上并不满足线性关系,弹性约束系统中的长大规律发生变化。The precipitation processes of D022 and L12 phases in Ni75Crl9Al6.0alloy were simulated based on the microscopic phase-field kinetic model and the microelasticity theory in this paper. During early precipitation process, D022 phases precipitated from the disorder matrix by the spinodal decomposition mechanism and the L12 phases precipitated by the non-classical nucleation growth mechanism, they both presented irregular shape, distributed randomly in the matrix. The elastic field produced by the lattice mismatch between the precipitates and the matrix has a strong influence on the late precipitation process. D022 and L12 phases showed anisotropic characteristic, and their precipitates presented cuboidal shape and distributed regularly along the elastic ＂soft＂ directions （[100] and [001]）, the highly preferential selected microstructure was formed during late precipitation process. The growth law was changed in the elastical strain system, there was no linear relationship between the cube of the average precipitate size and the ageing time as predicted by the classical Lifshitz-Slyozov-Wagner theory.

关 键 词：Ni75cr19Al6.0合金 沉淀 弹性应变能 微观相场 模拟 

分 类 号：TG111.5[金属学及工艺—物理冶金]