高能喷丸对AZ31镁合金耐腐蚀性及硬度的影响

采用高能喷丸对AZ31镁合金棒材端面进行表面自纳米化处理,利用失重法研究了AZ31镁合金喷丸试样和未喷丸试样在中性5%NaCl溶液中的腐蚀行为。利用扫描电子显微镜(SEM)、能量色谱仪(EDS)对塑性变形层腐蚀后的表面形貌、元素分布进行了表征,利用微观硬度计测试了由喷丸表面到基体的硬度变化。结果表明,喷完后AZ31镁合金试样的腐蚀速率明显大于未喷丸的试样,随着腐蚀时间的延长,喷丸试样的腐蚀率急剧减小,然后缓慢降低,在喷丸表面形成了1层厚度约150μm的塑性变形区,在喷丸表面有裂纹存在。晶粒细化显著提高了母材表面的微观硬度,喷丸表面的微观硬度最高达到135HV,是母材的2倍多。

Effects of high energy shot peening for magnesium alloy AZ31 on the corrosion properties and microhardness

The cross section surface of magnesium alloy AZ31 bar was treated for nanograins by means of high energy shot peening(HESP) and the corrosion of magnesium alloy AZ31 treated for nanograins by means of high energy shot peening in 5% NaCl solution was investigated.The corrosion surface appearances were analysed by SEM,the surface components of magnesium alloy AZ31 after corrosion were characterized by EDS,and the microhardness was tested by microhardness tester form plastic deformation layer to base.Results showed that the corrosion rate of the sample treated for nanograins by means of high energy shot peening higher,and the corrosion rate first decreased dramatically,then decreased slowly.The thickness of plastic degeneration was about 150μm,where existed cracks.The highest hardness was 135HV in the plastic degeneration zone,which was two times of base.