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开发了一种制备A356铝合金半固态浆料的搅拌工艺。与现有的机械搅拌和电磁搅拌不同的是该搅拌工艺是在熔融金属开始凝固前进行搅拌,其搅拌的作用是使初生晶均匀分布而不是破碎枝晶,并研究了搅拌棒的材质、插入熔体的温度、旋转速度及其直径对初生晶的形状、尺寸和分布的影响。结果表明,当搅拌棒与熔融金属的材料相同时,搅拌棒表面作为初生晶体的形核位点,生成众多的初生晶核,随着搅拌棒的旋转这些初生晶核不断地从棒表面分离进入熔体中,引起初生晶的细化和球化。通过优化搅拌棒插入熔体的温度、旋转速度及其直径等工艺参数,可以获得尺寸均匀细小的近球形初生晶的理想半固态浆料。
A stirring process for preparing A356 aluminum alloy semi-solid slurry was developed. Different from the existing mechanical agitation and electromagnetic agitation, the agitating process is to agitate the molten metal before it begins to solidify. The agitating function is to uniformly distribute the primary crystal instead of dendrites, and the material of the agitating rod is studied. Effect of Melt Temperature, Rotation Speed and Diameter on Shape, Size and Distribution of Primary Crystals. The results show that when the stir bar and the molten metal are the same, the surface of the stir bar acts as the nucleation site of the primary crystal and a large number of primary nuclei are generated. With the rotation of the stir bar, the primary nuclei are continuously separated from the surface of the bar In the melt, the primary crystal refinement and spheroidization are caused. By optimizing the process parameters such as the temperature, rotation speed and diameter of the melt, the ideal semisolid slurry with nearly spherical primary crystals with uniform size can be obtained.