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以压铸成型AZ91D镁合金为对象,研究了试样硬度与试验载荷对合金摩擦磨损行为的影响,借助电子扫描电镜(SEM)和X射线能谱仪(EDS)对磨痕面、磨屑的分析,初步探讨了磨损机理。结果表明:压铸成型AZ91D镁合金的充型过程对其摩擦磨损行为的影响明显,型腔端部硬度较高、摩擦系数相对稳定、磨损率较低,中部因存在铸造杂质、初生α相或少量β相等缩松、缩孔缺陷,其摩擦磨损特性相对较差。较低载荷下,因摩擦面与大气充分接触且存在大量的脱落磨粒,其磨损形式为氧化磨损和磨粒磨损的混合机制。随着载荷的增大,摩擦面可观察到唇边及塑性变形迹象,磨屑由小变大并连接成长条,即将脱落的磨屑与磨痕面局部连接处存在微裂纹,磨损机制由磨粒磨损向粘着磨损、熔融磨损逐渐转变。
The effects of specimen hardness and test load on the friction and wear behavior of the alloy were investigated by die-cast AZ91D magnesium alloy. The wear scar and wear debris were analyzed by SEM and X-ray EDS , Initially discussed the wear mechanism. The results show that the filling process of the die-cast AZ91D magnesium alloy has obvious influence on the friction and wear behavior. The die end hardness is high, the friction coefficient is relatively stable and the wear rate is low. The middle part has the defects of casting impurities, β is equal to shrinkage, shrinkage defects, the friction and wear characteristics are relatively poor. Under low load, due to the friction surface in full contact with the atmosphere and the presence of a large number of exfoliative abrasive, the wear form of oxidation wear and abrasive wear hybrid mechanism. With the increase of load, the friction surface can be observed lip and plastic deformation of the signs of wear debris from small to large and connected into a long strip, the upcoming fall off the wear debris and wear scar local connection at the existence of microcracks, the wear mechanism from the grinding Grain wear to adhesion wear, melt wear gradually change.