(中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083)
摘 要: 采用快速凝固氣體霧化工藝制備Al-27%Si合金粉末，研究合金粉末形貌和熱處理對(duì)組織的影響，利用X射線衍射儀和顯微硬度計(jì)等對(duì)Al-27%Si合金粉末中硅相的析出與長(zhǎng)大進(jìn)行表征。結(jié)果表明：快速凝固Al-27%Si合金粉末由基體α(Al)相、塊狀β-Si相和枝晶狀共晶硅相組成；經(jīng)熱處理后，β-Si相發(fā)生粗化，共晶硅相逐漸轉(zhuǎn)變?yōu)閴K狀相且發(fā)生粗化；在500 ℃下加熱保溫后，α(Al)相和β-Si相的衍射峰強(qiáng)度隨時(shí)間延長(zhǎng)而增大，α(Al)相衍射峰向低角度偏移；合金粉末顯微硬度在500 ℃下加熱，初期有下降趨勢(shì)，但隨時(shí)間延長(zhǎng)，不再下降，而是維持相對(duì)穩(wěn)定。
關(guān)鍵字: 快速凝固；Al-27%Si合金粉末；形貌；組織；熱處理；顯微硬度
（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
