高能电子束处理对AZ91镁合金耐磨性影响

研究了AZ91镁合金电子束表面处理的耐磨性.结果表明,在不同处理条件下,AZ91镁合金表面分别形成了厚度为20～60μm的表面熔凝层;脉冲电流和脉冲次数对表面熔凝层厚度具有较大影响,而加速电压的影响不大.随着脉冲电流的增加, Mg_(17)Al_(12)相对应的衍射峰强度呈现上升趋势,并且在处理过的AZ91镁合金中可看到AlMg亚稳相的存在.显微硬度测试结果表明,处理层硬度比基体组织的硬度有所提高,最表层可达到基体组织的2倍.磨擦系数和表面磨损量均有不同程度下降,耐磨性明显提高主要是由于快速熔凝导致晶粒细化引起的.

Effect of Pulsed High Energy Electron Beam Treatment on the Wear

The effect of pulsed high-energy electron beam on the surface modification of AZ91 magnesium alloy has been studied. The results show that the re-melted coatings (20~60 mm in thickness) on the surface of AZ91 magnesium alloy has been obtained under different treatment conditions. It was found that the thickness of the melted surface layer varies with the electron beam current and numbers of pulses, but the voltage has a minimal effect. The intensity of the diffraction peak assigned to Mg17Al12 increases with the increase of the electron beam energy, and a metastable AlMg phase has also been found from the XRD patterns of the treated AZ91 alloy. The treated surface layer exhibits a higher hardness than the AZ91 alloy, and the hardness of the topmost layer is two times as higher as the substrate. The friction coefficient and the wear volume of AZ91 alloy after electron beam treatment decrease obviously. The wear resistance of treated samples increases obviously, may be due to the high hardness from the grain refinement