(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 采用快速凝固气体雾化工艺制备Al-27%Si合金粉末，研究合金粉末形貌和热处理对组织的影响，利用X射线衍射仪和显微硬度计等对Al-27%Si合金粉末中硅相的析出与长大进行表征。结果表明：快速凝固Al-27%Si合金粉末由基体α(Al)相、块状β-Si相和枝晶状共晶硅相组成；经热处理后，β-Si相发生粗化，共晶硅相逐渐转变为块状相且发生粗化；在500 ℃下加热保温后，α(Al)相和β-Si相的衍射峰强度随时间延长而增大，α(Al)相衍射峰向低角度偏移；合金粉末显微硬度在500 ℃下加热，初期有下降趋势，但随时间延长，不再下降，而是维持相对稳定。
关键字: 快速凝固；Al-27%Si合金粉末；形貌；组织；热处理；显微硬度
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The rapidly solidified powders of Al-27%Si alloy were manufactured by gas atomization process. The effects of morphologies of alloy powders and heat treatment on the microstructure were studied. The precipitation and growth of silicon phase were investigated with X-ray diffractometer and microscope hardness tester. The results show that the rapidly solidified powders of Al-27%Si alloy are composed of α(Al) phase, β-Si bulk phase and dendritic structure eutectic silicon phase. After heat treatment, the β-Si bulk phase is coarsened and the eutectic silicon phase is changed to bulk phase and then coarsens. When held at 500 ℃, the diffraction peak intensities of the α(Al) phase and β-Si phase are enhanced with the time prolonging, and the position of the α(Al) phase peak shifts to lower angle. At the beginning of heat treatment at 500 ℃, the microhardness of the alloy powers decreases, followed by remaining relatively constant as the time prolonging.
Key words: rapid solidification; Al-27%Si alloy powders; morphologies; microstructures; heat treatments; microhardness
