X.T.Liu
,
J.Z.Cui
金属学报(英文版)
Microstructure evolution of wrought aluminum alloy extruded rods and the mechanism of liquid phase formation during reheating were investigated. And the relation between the volume fraction of liquid phase and the recrystallization microstructure was proposed. The results show that increase in reheating temperature and time can augment the volume fraction of liquid phase and accelerate the grain spheroidization, as a result of which the requirement of semi-solid forming can be satisfied. Due to the higher aberration energy of grain boundary, the melting point is lowered as a result of the easy diffusion of atoms. At higher reheating temperature the grain boundary melts, the growth of the recrystallized grain is inhibited and the grain is refined. The composition of the low melt-point phase along the recrystallized grains was determined using EDS. It can be seen from the experimental results that when the extrusion rod of the wrought aluminum alloy is reheated at 610℃ for 20min, perfect fine equiaxial grains can be obtained, the average grain size is about 66.34μm and the volume fraction of solid phase is about 68%.
关键词:
wrought aluminum alloy
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null
,
null
林高用
,
雷玉霞
,
郭道强
,
许秀芝
,
张宗鹏
中国有色金属学报
采用正交实验法和金相、力学性能、扫描电镜、能谱等测试手段对自主研发的变形Al-Si-Cu-Mg合金进行固溶和时效强化研究,并探究热处理过程中其组织特征的变化规律.结果表明:通过固溶(495℃,90 min,水冷)和时效(170℃,4h,空冷)处理后,合金的硬度提高31.3％,强度提高3.3倍.固溶过程中,大量Si、Cu和Mg原子固溶于基体中,起到强烈的固溶强化作用;过剩的共晶Si逐渐发生明显粒状化;剩余的大块θ相和Q相发生球化.时效过程中,细小针状强化相θ”和细小板条状Q'相在基体的(100)面上大量析出,分布均匀,对合金起到强烈的沉淀强化效果;过剩Si主要通过扩散附着于共晶Si表面析出.
关键词:
变形铝合金
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固溶
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时效
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正交实验
,
力学性能
