浇注温度对AlSi_7Mg合金显微组织的影响

Effect of Pouring Temperatures on the Microstructures of the Semi-Solid AlSi_7Mg Alloy

研究了不同的浇注温度对铸造ＡｌＳｉ７Ｍｇ合金凝固组织的影响．实验表明：当浇注温度 接近液相线温度时，ＡｌＳｉ７Ｍｇ合金中的初生α－Ａ１凝固成球状或粒状，晶粒细小，分布均匀；获得 球状或粒状ＡｌＳｉ７Ｍｇ合金半固态坯料的最佳浇注温度为６１５℃；在接近液相线温度下浇注，较快 的合金熔体冷却速度、浇注引起的合金熔体流动和大范围的同时凝固促使Ａ１Ｓｉ_７Ｍｇ合金形成 球状或粒状的初生α－Ａｌ组织．

The effect of different pouring temperatures on the microstructures of A1Si_7Mg alloy has been researched. When the pouring temperature is close to the liquidus temperature of A1Si_7Mg alloy, the primary α-A1 in the billets of A1Si_s7Mg alloy solidifies into spherical or nodular grains which are small and distributed homogeneously. In order to obtain non-dendritic semi-solid billets, the appropriate pouring temperature is 615℃. The faster cooling rate,the melt flowing and larger solidification region induced by the near liquidus pouring temperature promotes the formation of spherical or nodular primal α-A1.