超声波对Al-20Si合金中初晶Si的影响

采用高能超声波对Al-20Si合金熔体进行处理,研究超声波以不同的导入方式对过共晶Al-Si合金中初晶Si的细化效果的影响。试验表明,在Al-20Si合金凝固过程中进行超声波处理,可以促进形核,破碎组织中粗大块片状初晶Si,减小晶粒尺寸,提高圆整度,并使其分布均匀。由于超声波的衰减效应,采用不同方式导入超声波进行处理时,对合金凝固组织的作用效果有较大区别。采用超声波导入杆在距熔体中心1/2半径处做环绕运动导入超声波,能够对初晶Si产生较好的细化效果,所获得的凝固组织细化区域更大,初晶Si分布更加均匀。

Effects of Ultrasonic on the Primary Silicon in Hypereutectic Al-20Si Alloy

The refining effects and action mechanism of high-intensity ultrasonic on the primary Si in hypereutectic Al-Si alloy were investigated by treating Al-20Si melt with different sonophoresis ways. The results show that the nucleation rate in the alloy during solidification process can be increased by high-intensity ultrasonic treatment, where the shape of the primary Si is changed from the coarse plank structure into spherical ones with uniform distribution and the decrease of grain size. Refining effects are significantly different by treating with different sonophoresis methods due to the attenuation of the ultrasonic. The experimental results indicate that the primary Si is well refined with the more uniform distribution in the alloy, and the refinement area of solidification can be enlarged by treating with high-intensity ultrasonic when the ultrasonic rod is introduced with the circle movement at 1/2 of ingot casting radius to the center of melt.