采用高速颗粒轰击技术在7A52铝合金表面制得一定厚度纳米结构表层,利用扫描电子显微镜和透射电子显微镜观察了表面纳米晶层的微观结构特征,利用多功能纳米压痕仪和往复式摩擦磨损试验机测试了样品表面纳米化前后的硬度和耐磨性能.结果表明:7A52铝合金经高速颗粒轰击处理后样品表层形成了厚度约90 μm塑性变形层,最表层晶粒尺寸约为8～20 nm；表面纳米晶层的显微硬度约为原始样品的1.76倍；在油润滑的低载荷和中等载荷条件下,表面纳米化抛光样品的磨损量为原始样品的1/2～1/3；表面纳米化样品的磨损机制为磨粒磨损和黏着磨损,而原始样品的磨损机制为黏着磨损和疲劳磨损,表明其具有优异的耐磨性能.%Nanocrystallization surface layer was fabricated by means of high speed particles bombarding on the surface of 7A52 aluminum alloy. The microstructure features of surface nanocrystalline layer were characterized by Scan Electron Microscropy (SEM) and Transmission Electron Microscropy (TEM). The micro-hardness of the sample before and after high speed particle bombording was measured by nano-indentation and the wear performance was studied by tribometer. The result is that the deformation layer with the thickness a-bout 90 μm was formed and the size of grain on the top surface was about 8~20 nm after the sample was bombarded by supersonic fine particle; the micro-hardness of the surface nanocrystalline layer was 1. 7 times more than that of the original sample. Under low loads, middle loads and lubricated conditions,the wear loss was a-bout 1/2 ~ 1/3 of the original sample. The wear mechanism of surface nanocrystallization sample which showed good wear performance is abrasive and adhesive wear,while the wear mechanism of the original sample is adhesive and fatigue wear.
展开▼
