超声冲击对AZ91D镁合金耐磨性能及显微硬度的影响

The effect of ultrasonic impact treating on wear resistance and micro-hardness of AZ91D magnesium alloy

摘要:

模板采用HJ-III型超声冲击设备对AZ91D镁合金表面了冲击处理，利用高倍透射电子显微镜研究了超声冲击细化晶粒的机理。分别研究了经超声冲击处理和未经处理的AZ91D镁合金的耐磨性能。用扫描电镜和显微硬度计研究了超声冲击处理对微观组织和显微硬度的影响。结果表明，超声冲击使AZ91D镁合金的表面出现了严重的塑性变形，塑变层深度约为120 祄，表面组织明显得到细化。并在AZ91D镁合金的冲击表面出现了残余压应力。超声冲击可极大的提高AZ91D镁合金的耐磨性能和显微硬度。耐磨性能和显微硬度随超声冲击电流和冲击时间的增加而提高，表明超声冲击是提高AZ91D镁合金耐磨性能和显微硬度的一种有效方法。

Abstract:

The surface of AZ91D magnesium alloy was treated using HJ-III type ultrasonic impact treating (UIT) machine and the grain refining mechanism of ultrasonic impact treating was investigated by means of HTEM. The wear resistance of AZ91D magnesium alloy was experimentally studied both for the treated and un-treated samples respectively. The effect of UIT on the microstructure, and micro-hardness were also investigated using SEM and micro-hardness tester. The experimental results indicate that the severe plastic deformation in the surface of AZ91D was formed by UIT, the thickness of the plastic deformation layer is about 120 祄, and the grains are highly refined and compressive residual stress in the surface of AZ91D was also obtained. The wear resistance and micro-hardness of AZ91D alloy could be greatly improved via UIT. The wear resistance and micro-hardness are promoted by increasing the UIT current and time, which indicates that the UIT is a useful method to increase the hardness and wear resistance of AZ91D alloy.