ZL205A铝合金近液相线等温半固态组织转变特性  

Behavior of Microstructure Evolution of ZL205A Cast Aluminum Alloy during Semi-Solid Isothermal Annealing Process

作　　者：杨光昱[1] 介万奇[1] 张润强 郝启堂[1] 李杰华[1] 

机构地区：[1]西北工业大学材料学院,陕西西安710072 [2]西北工业技术研究院,陕西西安710065

出　　处：《稀有金属材料与工程》2007年第10期1717-1721,共5页Rare Metal Materials and Engineering

基　　金：国家重点基础研究发展计划("973")项目(2006CB605202)

摘　　要：研究了ZL205A铝合金在近液相线不同等温温度和等温时间条件下的微观组织转变规律。结果表明,α(Al)晶粒直径与等温时间满足关系式r3r03=k't。系数k′值随等温温度变化,在622℃和631℃条件下对应的k′值分别为4.288×10-10m3/s和5.962×10-10m3/s。实验合金的等温过程基本上分为球化预备阶段、球化阶段和长大粗化阶段。等温温度提高,固相体积分数也随之降低,有利于加速α(Al)晶粒球化和获得均匀的球状等轴固相颗粒。实验合金等温组织演变过程是溶质传输和空位扩散、以及液固界面张力共同作用的结果。溶质扩散作用在开始阶段起主导作用,而界面张力在中后期占主要作用。The behavior of microstructure evolution of ZL205A aluminum cast alloy during semi-solid heat-treatment process for different holding time was studied. It was found that the relationship between the average diameter of α （Al） grains and the isothermal holding time fit the formula r^-3-r0^3=k＇-t, where the constant k＇ varied with the holding temperature, which is equal to 4.288 × 10^10 m^3/s and 5.962 × 10^10 m^3/s at 622 ℃ and 631℃, respectively. The semi-solid isothermal annealing process of experimental alloy can be divided into three stages, i.e. preparation stage, spheroidization stage and coarsen stage. A higher holding temperature could accelerate spheroidization of α （Al）. The microstructure evolution of the alloy is attributed the result of the diffusion of the solutes as well as vacancies, and the grain boundary tension. The diffusion of the solutes plays a leading role in the preparation stage, and the grain boundary tension dominates the late stages, e.g. spheroidization stage and coarsen stage.

关 键 词：ZL205A铝合金 等温半固态 微观组织 粗化 

分 类 号：TG146.21[一般工业技术—材料科学与工程]