两种压铸镁合金的微动磨损行为研究

采用液压高精度材料试验机考察了压铸镁合金AZ91D和AM60B在平面-球面接触条件下的微动磨损行为,研究了循环次数、位移幅值、法向载荷和频率等参数对镁合金摩擦磨损性能的影响,分析了其磨斑表面和磨屑的微观形貌,并探讨了其微动磨损机理.结果表明:镁合金AZ91D和AM60B的摩擦系数随着法向载荷的增加而减小,磨损体积损失随频率增加而减小;AZ91D镁合金的抗微动损伤能力优于AM60B镁合金,二者的微动磨损机理相似,其主要磨损形式包括粘着磨损、表面疲劳(脱层)磨损、磨粒磨损以及明显的氧化磨损.

Fretting Wear Behavior of Two Kinds of Die Cast Magnesium Alloy

The fretting wear behaviors of AZ91D and AM60B magnesium alloys self-paired in a plane-on-ball configuration were investigated using a universal material tester of highly accurate displacement control. The effects of the number of cycle, amplitude of slip, normal load, and frequency on the friction and wear properties of the Mg alloys were analyzed. The morphologies of the fretted surfaces and wear debris of the Mg alloys were observed using a scanning electron microscope. The results indicated that the two die cast magnesium alloys had fretting wear mechanisms including adhesion wear, surface fatigue wear, abrasive wear, and oxidation wear. The fretting wear behaviors of the two Mg alloys were closely dependent on the testing parameters such as frequency, slip amplitude, and normal load, while the Mg alloy AZ91D showed better fretting wear resistance than the Mg alloy AM60B. This could be attributed to the larger plasticity of the AM60B than the AZ91D. In other words, it needed much more time for the AM60B of larger plasticity to form a stable third-body layer capable of decreasing wear during the fretting process under the same test conditions, therefore AM60B had poorer fretting wear resistance than AZ91D.