Mg-Gd-Zn-Zr镁合金的摩擦磨损行为

Tribological behavior of Mg-Gd-Zn-Zr magnesium alloys

利用光学显微镜、扫描电镜、能谱仪、显微硬度计和摩擦磨损试验机研究了不同Gd含量的固溶态Mg-xGd-1Zn-0.4Zr(x=3,6,9 wt%)合金和不同Zn含量的固溶态Mg-6Gd-yZn-0.4Zr(y=0.5,1,2 wt%)合金的显微组织、硬度、摩擦因数、磨损率和磨损形貌。结果表明,随着Gd或Zn含量的增加,固溶态合金的晶粒有所细化,合金的硬度上升,摩擦因数变化较小。随着Gd含量的增加,合金的磨损率稍有增加;而随着Zn含量的升高,合金的磨损率降低,当Zn含量为2%时,其磨损率比Zn含量为0.5%合金的磨损率降低了24%。5组合金主要发生了磨粒磨损、氧化磨损和塑性变形。当Gd含量为9%时,还观察到粘着磨损。Mg-Gd-Zn-Zr合金的耐磨性主要取决于磨损机制,与硬度无直接对应关系。

Microstructure,microhardness,friction coefficient,wear rate and worn surface morphology of solution treated Mg-xGd-1Zn-0.4Zr(x=3,6,9 wt%)alloys with different Gd contents and solution treated Mg-6Gd-yZn-0.4Zr(y=0.5,1,2 wt%)alloys with various Zn additions were studied by means of optical microscope,scanning electron microscope,energy spectrometer,microhardness tester and friction and wear testing machine.The results show that the grains refine,the microhardness increases,and the friction coefficient shows slight change with Gd or Zn content increasing.The wear rate of the alloys increases slightly with the increase of Gd content,whereas,it decreases with the increase of Zn content.Compared with the alloy containing 0.5%Zn,the wear rate of the alloy containing 2%Zn presents 24%reduction.The main wear mechanisms of the five alloys are abrasion,oxidation and plastic deformation,as well as adhesion for the alloy containing 9%Gd.The wear resistance of the alloys depends on the wear mechanisms and has no direct relation to the hardness.