(重慶大學(xué) 材料科學(xué)與工程學(xué)院， 重慶 400044)
摘 要: 對3種典型成分的鋁硅合金（Al-20%Si、 Al-12%Si和Al-7%Si）進行了熔體溫度處理凝固組織變化規(guī)律的比較研究。結(jié)果表明： 在Al-12%Si共晶合金熔體處理組織中存在α枝晶與初晶硅共存以及α枝晶在一定處理條件下可以完全消失的現(xiàn)象； 3種成分Al-Si合金的α枝晶及初晶硅的形態(tài)尺寸隨過熱溫度、 靜置時間增加出現(xiàn)周期性的變化規(guī)律， 出現(xiàn)最小尺寸的溫度、 時間并不完全一致；熔體溫度處理對Al-7%Si中枝晶大小、形態(tài)等有一定影響， 但細化效果不明顯。 在鋁硅合金中， 硅原子微觀有序團簇和鋁有序偏聚原子團簇可能存在于不同的溫度區(qū)間， 鋁有序偏聚原子團簇存在的溫度區(qū)間更靠近溫度軸，硅原子微觀有序團簇具有比鋁有序偏聚原子團簇更強的結(jié)合能。
關(guān)鍵字: 鋁硅合金； 熔體溫度處理； 共晶； 原子團簇； 凝固組織
of three typical Al-Si alloy
（College of Materials Science and Engineering,
Chongqing University, Chongqing 400044, China）
Abstract: The solidification microstructures of hypoeutectic, eutectic and hypereutectic Al-Si alloys by melt temperature treatment were studied comparatively. The results show that, in the microstructures of Al-12%Si alloy, dendrites of α phase coexist with pre-precipitate silicon, and under a certain treatment condition, dendrites of α phase would disappear; the sizes of dendrite of α phase and pre-precipitated silicon change regularly with increasing temperature or time, the temperature and time that the smallest sizes of the phases appear among the alloys is not corresponded; the melt temperature treatment have certain effect on the sizes of dendrite of α phase, but the effect is limited. It is considered that in the TTT diagram of liquid structure and temperature of Al-Si alloys, silicon atom clusters and aluminum atom clusters would exist in different temperature zones, the position of aluminum atom clusters is closer to temperature axis than that of silicon atom clusters, the bond energy of the silicon atom clusters is the stronger than that of aluminum atom clusters.
Key words: Al-Si alloy; melt temperature treatment; eutectic; atom clusters; solidification microstructures
