7075铝合金在VG46油润滑工况下的扭转复合微动磨损特性

Dual-rotary fretting wear behavior of 7075 aluminium alloy under VG46 oil-lubricated condition

采用球/平面接触方式,考察7075铝合金在VG46油润滑工况下不同倾斜角度和角位移幅值对扭转复合微动磨损特性的影响。利用光学显微镜(OM)、扫描电子显微镜(SEM)分析7075铝合金的磨痕表面及剖面形貌、磨损机制,用双模式表面轮廓仪分析磨损体积。结果表明:润滑油对扭转复合微动运行和损伤机制存在显著影响,润滑油明显改变微动运行区域,随着倾斜角度的增加,微动的混合区逐渐缩小甚至完全消失。微动运行区域对润滑油的润滑性能也有重要影响,在部分滑移区,微滑仅发生在接触边缘,润滑油对微动的影响甚微;在混合区,润滑油渗入表面微裂纹加速了疲劳裂纹的扩展;在滑移区,接触界面间形成了润滑油膜,显著地减缓了微动损伤。

The dual-rotary fretting wear behaviors of 7075 aluminium alloy flats against GCr15 steel ball in VG46 oil were studied under various tilt angles and angular displacement amplitudes. The kinetic behaviors of the dual-rotary fretting of 7075Al/GCr15 contact pairs were analyzed. The fretting scars surface damages, cross-section morphologies and wear mechanisms were characterized through optical microscope （OM） and scanning electrical microscope （SEM）, and the wear volume was measured by dual mode surface profilometer. The results show that the oil has significant effect on the fretting running characteristics and the damage mechanisms, the fretting running condition can be obviously changed by oil media. With the increase of the tilt angles, the mixed fretting regime gradually decreases or even disappears completely. In addition, the lubricating properties are also strongly dependent upon the fretting running regimes. In partial slip regime （PSR）, the micro-slip only occurs in the contact edge, and the lubricating oil has a very small influence on the fretting damage. In mixed fretting regime （MFR）, the oil can easily penetrate into the micro-cracks on the surface and promote the propagation of cracks. In slip regime （SR）, the lubricating oil can effectively mitigate DRF damage, because the oil can penetrate into the contact interface and form a lubricant film.