颗粒增强铝基复合材料6066Al／SiCp的时效析出特性

Aging Precipitation Behavior of SiC Paticulate Reinforced 6066 Aluminium Alloy Fabricated by Spray Atomization and Co -deposition

摘要:

采用喷射共沉积工艺制备了6066Al基体铝合金以及含不同体积分数增强颗粒的6066Al/SiCp铝基复合材料，与常规则熔铸＋挤压的基体铝合金比较，喷射共沉积基体铝合金和复合材料的力学性能峰值时效时间明显缩短，即喷射共沉积6066Al和6066Al/SiCp颗粒增强铝基复合材料发生加速时效现象。对材料的微观组织进行常规金相和透射电镜观察，分析了SiCp增强陶瓷颗粒以及喷射共沉积工艺对材料时效析出行为的影响。研究表明：喷射共沉积工艺所形成的非平衡组织中溶质原子浓度高，时效析出驱动力大，有利于时效过程溶质原子扩散和第二相的形核。喷射共沉积材料细化的晶粒组织及复合材料中的高密度位错有利于非均匀形核，是加速材料时效析出动力学过程的主要原因。

Abstract:

Unreinforced 6066aluminium alloy a nd the alloy reinforced by SiC partic ulate with various volume fraction were fabricated by spray atomization and co -deposition,and also the unreinforced alloy was fabr icated by as -melten as a contrast,an d the materials were then extruded.It was observed that the aging respon ses of 6066Al and 6066Al /SiCp fabric ated by spray atomization and co -dep osition were accelerated.Metal-lography and transmission electron microscopy(TEM)were utilized to inspect the microstructures of the materials.The effect of processing route and the increased dislocation density resulted from the addition of SiC p articulate into metal matrix on the a ging behavior of the materials was di s-cussed.It is shown that the concentr ation of solute atomand kinetics of phase transformation in materials fa bricated by spray atomization and co-deposition are much higher than the o thers in this paper.Moreover,the decrease in grain size induced by spray atomization and co -deposition and the increased dislocation density in composites resulted from the ad dition of SiC particulates lead to su fficient positions for inhomogeneo ns nucleation and thus accelerate the k inetics of aging precipitation of th e materials involved in this study.