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以AZ91D镁合金为对象,研究了触变成型坯料保温温度、加热时间和模具预热温度对摩擦磨损性能的影响,通过磨痕面、磨屑的SEM和EDS分析,优化了成型工艺参数并探讨了磨损机理。结果表明:触变成型工艺能显著提高合金的耐磨性,相对理想的成型工艺参数为保温温度585℃、加热时间60 min、预热温度300℃。较低载荷下,AZ91D镁合金主要发生氧化磨损,摩擦表面易形成MgO、Al_2O_3氧化薄膜,其在连续接触的切应力往复作用下极易脱落而生成新的氧化膜,磨屑呈细小颗粒。随着试验载荷的增加,磨痕面可观察到唇边撕裂和不同程度的塑性变形迹象,合金发生轻微剥层磨损、轻微粘着磨损到严重粘着磨损的转换,磨屑由片状剥层向棉絮团状转变,堆积在磨道两侧且粘着力明显增加。
The effects of holding temperature, heating time and preheating temperature on the tribological properties of AZ91D magnesium alloy were studied. SEM and EDS analysis of wear scar and wear debris were carried out to optimize the molding process parameters Discussed the wear mechanism. The results show that the thixoforming process can significantly improve the wear resistance of the alloy. The relatively ideal molding process parameters are the holding temperature of 585 ℃, the heating time of 60 min and the preheating temperature of 300 ℃. Under low load, the AZ91D magnesium alloy mainly oxidizes and wears down, and the surface of MgO and Al_2O_3 is easily formed on the friction surface. It is easy to fall off under the reciprocating action of continuous contact shear stress to form a new oxide film. With the increase of test load, the wear scar surface can be observed tear and varying degrees of plastic deformation of the signs of wear and tear of the alloy slight peeling wear, slight adhesive wear to severe adhesive wear conversion, wear debris from sheet peel to the Cotton swarmed transition, accumulation in both sides of the mill and adhesion increased significantly.