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采用低于Al-Si合金共晶点温度(577℃)加热保温处理,研究过共晶Al-24%Si合金在不同的加热扩散温度和保温时间下初晶硅形态的演变。结果表明:加热扩散温度为550℃,保温时间分别为3、6、9和12 h时,随保温时间的延长,粗大块状或花瓣星状的初晶硅趋于向近球状转变,且尺寸随保温时间的延长而变得细小;当保温时间为9 h,加热扩散温度为450、510、530和550℃时,随加热扩散温度的升高,初晶硅的尺寸越细小,圆整度提高,通过选择合适的加热扩散温度和保温时间进行处理可以起到使初晶硅球化和细化的效果,从而提高合金的力学性能。
The evolution of the morphology of primary silicon under different heating diffusion temperature and holding time was studied by heating and soaking below the eutectic temperature (577 ℃) of Al-Si alloy. The results show that when the diffusion temperature is 550 ℃ and the holding time is 3, 6, 9 and 12 h respectively, the coarse or petal star-shaped primary silicon tends to change toward the near-sphere with the increase of holding time. When the holding time is 9 h and the heating diffusion temperature is 450, 510, 530 and 550 ℃, with the increase of heating diffusion temperature, the size of the primary silicon is finer and the roundness Improve, by selecting the appropriate diffusion temperature and holding time heating can play the primary crystallization of silicon and refinement effect, thereby enhancing the mechanical properties of the alloy.