超声冲击MB8镁合金的耐磨性与显微硬度试验（英文）

Experimental Research on Microhardness and Wear Resistance of MB8 Magnesium Alloy Treated by Ultrasonic Impact

采用HJ-III型超声冲击设备对MB8镁合金表面进行冲击处理,利用高倍透射电子显微镜研究了超声冲击表层的微观组织及晶粒细化机制。对经超声冲击处理和未冲击处理的MB8镁合金的耐磨性能进行了对比研究。采用扫描电镜和显微硬度计分别研究了超声冲击处理对磨损表面形貌和显微硬度的影响。结果表明:超声冲击使MB8镁合金的表面出现了严重的塑性变形,塑变层深度约为180μm,表面组织明显得到细化。耐磨性能和显微硬度随超声冲击时间的延长而提高。与未冲击试样相比,在冲击时间为6 min时,冲击电流为1.2 A时,冲击试样的显微硬度和耐磨性分别提高了102.8%和51.83%。

The surface of MB8 wrought magnesium alloy was treated by HJ-III type ultrasonic impact treating（UIT） machine. The microstructures of the treated surface were analyzed by an optical microscope, and the grain refining mechanism of UIT was investigated by High Resolution Transmission Electron Microscopy（HRTEM）. The wear resistance of MB8 wrought magnesium alloy was experimentally researched both with the treated and untreated specimens. The effect of UIT process on the microstructure and microhardness were also investigated using scanning electron microscope（SEM） and microhardness tester. The results indicate that the grains on the top surfaces of MB8 are highly refined. The severe plastic deformation is formed by UIT, and the thickness of the plastic deformation layer is approximately 180 μm. The microhardness and wear resistance of the treated surface layer of MB8 can be enhanced significantly compared to that of the untreated specimens. The longer the UIT time, the greater of the microhardness and wear resistance the treated surface layer of MB8 will be. When the impact current is 1.2 A and impact time is 6 min, the microhardness and wear resistance of the treated sample is about 102.8% and 51.83% higher than that of the untreated specimen, respectively.