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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。
The melt of Al-20Si alloy was treated by high-energy ultrasonic to study the effect of ultrasonic wave on the refinement of primary Si in hypereutectic Al-Si alloy by different ways of introduction. Experiments show that the ultrasonic treatment during the solidification of Al-20Si alloy can promote the nucleation, break the coarse primary Si crystals in the structure, reduce the grain size, improve the roundness and make it evenly distributed. Due to the decay effect of ultrasonic waves, when the ultrasonic waves are introduced by different ways for processing, the effect on the solidified structure of the alloy is greatly different. The introduction of ultrasonic waves into the surrounding core at a radius of ½ of the center of the melt led to a better refinement effect on the primary Si with a more uniform refinement of the solidified structure and a more uniform primary Si distribution .