微量添加稀土元素Nd和Er对挤压态Mg-6.0Zn-0.5Mn镁合金干摩擦磨损性能的影响

Effects of Minor Addition of Nd and Er Elements on Dry Sliding Friction and Wear Characteristics of Extruded Mg-6.0Zn-0.5Mn Alloy

利用扫描电子显微镜、能谱仪、透射电镜、硬度计、3D轮廓仪和摩擦磨损试验机研究了复合添加微量Nd和Er元素对Mg-6.0Zn-0.5Mn合金干摩擦磨损性能的影响。结果表明,添加微量Nd和Er元素后,晶界处种类和数量更多的金属间化合物会阻碍晶界的迁移和滑移,基体中动态析出的β_(1)’相密度增大且平均长度减小,更多的动态析出相以及弥散分布的金属间化合物使基体的硬度,磨损量降低。Mg-6.0Zn-0.5Mn合金在5 N低载荷下的磨损机制以磨粒磨损为主,并伴有氧化磨损;当载荷增大至20 N,磨粒磨损明显减弱,氧化磨损程度增大。复合添加微量Nd和Er后,Mg-6.0Zn-0.5Mn-0.6Nd-0.3Er合金在低载荷(5 N)下的磨损机制以磨粒磨损为主,伴有氧化磨损和黏附磨损;由于耐磨性提高,当载荷增大至20 N时,磨损机制仍以磨粒磨损为主,黏附磨损程度有所减弱,并伴有氧化磨损。

The effects of Nd and Er elements on the friction and wear behavior of Mg-6.0 Zn-0.5 Mn alloy were studied by SEM,EDS,TEM,hardness tester,3 D profiler and friction and wear tester.The results show that more types and quantities of intermetallic compounds can hinder the migration and slip of the grain boundary,and the volume fraction of dynamic precipitatesβ_(1)’with a smaller average length increases,which increase the hardness of the matrix and reduce the wear rate of Mg-6.0 Zn-0.5 Mn-0.6 Nd-0.3 Er alloy.The wear mechanism of Mg-6.0 Zn-0.5 Mn alloy under a lower load of 5 N is mainly abrasive wear,accompanied by oxidative wear;when the load increases to 20 N,abrasive wear is weakened obviously and oxidative wear increases in Mg-6.0 Zn-0.5 Mn alloy.The wear mechanism of Mg-6.0 Zn-0.5 Mn-0.6 Nd-0.3 Er alloy under the load of 5 N is mainly abrasive wear,accompanied by oxidative wear and adhesion wear;due to the improved wear resistance,when the load increases to 20 N,the wear mechanism of Mg-6.0 Zn-0.5 Mn-0.6 Nd-0.3 Er alloy is still mainly abrasive wear,accompanied by oxidative wear and weakened adhesion wear.