钢表面多元共渗改性层的微动磨损行为研究

Study on Fretting Wear Behavior of Steel Modified by Gas Multi-element Penetration at Low Temperature

利用低温气体多元共渗技术将碳、氮、硫、氧元素同时渗入LZ50钢表面形成改性层。在对改性层进行表征的基础上,研究了改性层及LZ50钢基体在干态不同位移幅值下的微动磨损行为及其动力学特性,并采用扫描电子显微镜和轮廓仪对磨痕形貌进行了分析。结果表明:制备的多元共渗改性层厚度约60μm,基本由疏松层,化合物层和扩散层组成,化合物层硬度最高,为典型的高硬度多孔结构;改性层改变了LZ50钢的微动运行区域,使得混合区的范围缩小,滑移区向小位移方向移动;由于疏松层的固体润滑作用,与基体LZ50钢相比,在微动初期摩擦因数较低;多元共渗改性层可以显著降低LZ50钢的磨损,在部分滑移区损伤轻微,在混合区和滑移区,改性层的损伤主要表现为剥层和磨粒磨损。

The modified layer was prepared on the surface of LZ50 by gas multi-element （carbon, nitrogen, sulphur and oxygen） penetration at low temperature. Base on the characterizations of the modified layer, fretting wear tests of the modified layer and its substrate were carried out under different displacement amplitudes. Dynamic analyses combination with microscopic examinations through Scanning Electric Microscope and profilometer were performed. The results indicated the modified layer with a total thickness of 60 gm was consisted of loose layer, compound layer and diffusion layer, which presented typical porous structure with high hardness in compound layer. Fretting regimes of the modified layer were changed, i.e. the range of the mixed fretting regime was diminished, and the slip regime shifted to the direction of smaller displacement amplitude. Compared with the substrate, friction coefficient was lower in initial stage due to lubricating effect coming from the loose layer. Wear of material reduced greatly for the modified layer specimens. The damage in the partial slip regime was very slight, but in the mixed and slip regime, the damage mechanism of the modified layer was mainly delamination and abrasive wear.