马氏体钢干滑动磨损纳米梯度结构的形成机理研究

采用SFT-2M销盘式摩擦磨损仪对马氏体钢进行干滑动磨损试验. 通过扫描电镜、透射电镜和显微硬度计对滑动磨损后的显微组织进行了表征. 结果表明:显微组织的变化随着接触载荷的不同，受到不同磨损机制的主导. 在相对较低接触载荷下，马氏体板条在磨粒磨损机制下发生弯曲；在高接触载荷下，马氏体板条在黏着磨损机制下形成梯度结构. 滑动磨损引发大量塑性变形，在材料内部产生高位错密度的几何必要边界(GNBs)和伴生位错边界(IDBs)，导致层片结构的形成. 随着这两种边界数量的增大，层片间距减小，晶粒被分割为更小的晶粒，最终形成纳米层片结构. 

Investigation on Formation Mechanism of Nano-Gradient Structure in Dry Sliding Wear of Martensite Steel

Dry sliding wear test was carried out on a martensitic steel using a SFT-2M pin-on-disk friction tester. The microstructure after sliding wear was characterized by scanning electron microscope (SEM), transmission electron microscope (TEM) and microhardness tester. The results show that microstructural change was controlled by different wear mechanisms at both high and low contact loads. At a relatively lower load, martensite lath became bend under the mechanism of abrasive wear, whereas it formed a gradient structure at the mechanism of adhesive wear at the higher load. As a result of sliding wear-induced plastic deformation, high dislocation density of geometrically necessary boundaries (GNBs) and incidental dislocation boundaries (IDBs) was formed. This led to the formation of laminated structure. The lamellar spacing was greatly reduced and grains were partitioned into smaller grains with increasing number of GNBs and IDBs. Eventually, nano-laminated structure was generated.