SLM成形IN738LC合金的微动磨损行为及磨损机理

Fretting wear behavior and wear mechanism of IN738LC alloy formed by selective laser melting

本文通过高精度微动摩擦磨损试验机(SRV-V),以球/平面点接触模式对选区激光熔化(SLM)技术制备的IN738LC合金进行切向微动磨损实验,系统研究了恒定载荷条件下(50 N),不同位移幅值(50、100、150、200μm)试样的微动磨损行为及其磨损机理。结果表明:随着位移幅值增加,试样的摩擦因数和磨损体积逐渐增大,微动磨损运行状态由混合区逐渐转变为完全滑移区,50μm试样的磨损机理为轻微氧化磨损和疲劳磨损,200μm试样的磨损机理转变为氧化磨损、疲劳磨损和磨粒磨损。此外,磨痕中的微裂纹分布强烈依赖于微动区类型,即微裂纹出现在黏着区域和滑移区域的交界位置及完全滑移区域内。由于磨痕边缘存在犁削作用,磨痕形状由圆形变为椭圆形。

In this paper,tangential fretting wear experiments on IN738LC alloy produced by SLM technology were carried out using a high-precision fretting friction and wear testing machine(SRV-V)in the point contact mode of ball-on-flat,and the fretting wear behavior of specimens and their wear mechanisms were systematically investigated for different displacement amplitudes(50,100,150 and 200μm)under constant load conditions(50 N).The results indicate that the friction coefficient and wear volume of the specimen gradually increase with the increase of displacement amplitude.The fretting wear evolves gradually from the mixed fretting regime to the gross slip regime.The wear mechanism for the 50μm specimen is characterized by slight oxidation wear and fatigue wear,while that of the 200μm specimen involves oxidation wear,fatigue wear and abrasive wear.Additionally,the distribution of micro-cracks in abrasion mark is significantly reliant on the micro-motion regime type,fretting cracks can occur both at the intersection of adhesion and slip regime and within the gross slip regime.The wear mark shape transforms from circular to oval as a result of the ploughing activity of the mark edges.