7075铝合金扭转复合微动磨损研究

基于低速往复回转系统,通过改变回转系统旋转轴的倾斜角α,成功实现了球/平面接触状态下扭动微动和转动微动的复合,并研究了7075铝合金/GCr15钢球在倾斜角10°和40°及不同角位移幅值下的扭转复合微动行为.在动力学分析基础上,结合光学显微镜(OM)、扫描电子显微镜(SEM)、X射线能谱仪(EDX)、表面轮廓仪等手段分析了扭转复合微动运行行为及损伤机理.结果表明:7075铝合金的扭转复合微动的运行和损伤行为强烈依赖于倾斜角和角位移幅值;随着倾斜角的增加,扭动微动分量减少,转动微动分量增加,复合微动的混合区和滑移区向小角位移方向移动,损伤形貌的非对称性增加,同时磨损机制从剥层和氧化磨损逐渐转变为磨粒磨损和氧化磨损.

Dual-rotary Fretting Behavior of 7075 Aluminum Alloy

Base on a low-speed reciprocating rotary system,the combination of torsional fretting(TF) and rotational fretting(RF) under a contact of ball-on-flat was successfully realized by changing the title angle(α) of the shaft of rotary system.The dual rotary fretting(DRF) behavior of 7075 aluminum alloy against 52100 steel ball was investigated under tilt angles of 10°and 40° and varied angular displacement amplitudes.Dynamic analysis were performed in combination with microscopic examinations through optical microscopy,surface profilometer,scanning electric microscopy and energy dispersive analysis of X-ray.The results show that the running and damage behaviors of DRF of 7075 aluminum alloy were strongly dependent upon the tilt angle and angular displacement amplitude.With the increase of the title angle,the component of TF increased and the component of RF decreased accordingly.The mixed fretting regime and slip regime of DRF shifted to the direction of lower angular displacement amplitude with the increase of the asymmetry of damage morphology.Meanwhile,the wear mechanisms changed from delamination and oxidative wear to abrasive wear and oxidative wear.