W6Mo5Cr4V2钢氮离子注入表面改性层的摩擦学性能

Friction and Wear Behavior of the Surface-modified Layer of W6Mo5Cr4V2 Steel Implanted with Nitrogen Ions

对 W6 Mo5 Cr4V2钢进行氮离子注入 ,用销 -盘式摩擦磨损试验机考察了钢表面注入改性层的摩擦磨损性能 ;用扫描电子显微镜、俄歇电子能谱仪及微区 X射线衍射仪等考察了改性层的相组成、氮元素沿注入层深度方向的浓度分布及磨损机理 .结果表明 ,离子注入处理后钢表面显微硬度提高、残余压应力增大、表面粗糙度降、注入层中形成了大量细小弥散分布的硬质析出相ε- Fe2 - 3 N、Cr N及β- Cr2 N等 ,从而改善了材料的摩擦学性能 ,并导致磨损机理发生变化 .正交试验结果表明 ,氮离子注入对 W6 Mo5 Cr4V2钢摩擦学性能的改善程度与注入能量和注入剂量不成正比 ,注入参数存在最佳值 ,最佳注入能量为 10 0 ke V,注入剂量为 4× 10 1

W6Mo5Cr4V2 steel was implanted with N+ ions. The friction and wear behavior of the surface-modified layer on the steel surface was examined on a pin-on-disc friction and wear tester. The phase composition, the depth profile of N through the modified layer and the wear mechanisms of the surface-modified layer were investigated by means of scanning electron microscopy, Auger electron spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The results show that the ion implantation of the steel with N+ ions leads to considerable changes in the physical and mechanical properties as well as the chemical states of the surface-modified layer. Thus finely dispersed hard secondary-phase particles including Ε-Fe2-3N, CrN, and β-Cr2N were generated on the steel surface after the ion implantation. The strengthening effect of the secondary phases and the related eutectoids leads to the decrease of the surface roughness and the increase of the surface micro-hardness and the compressive stress. Subsequently a greatly improved friction and wear behavior of the surface-modified layer is reached. Moreover, the improvement degree of the friction and wear behavior of the surface-modified layer is highly dependent on the ion implantation parameters. The orthogonal analytical results indicate that the optimal friction and wear behavior of the surface-modified layer is reached at an ion implantation dose of 4×1017 ions/cm2 and at the energy of 100 keV.