接触载荷对7075铝合金扭转复合微动摩擦学行为的影响

Effect of contact load on dual-rotary fretting tribological behavior of 7075 aluminum alloy

在新型扭转复合微动试验机上,以7075铝合金平面/GCr15钢球配副为研究对象,研究不同接触载荷对7075铝合金扭转复合微动磨损行为的影响。在动力学特性分析的基础上结合磨痕形貌微观观察,研究7075铝合金扭转复合微动的磨损机理。结果表明:接触载荷明显地改变微动运行区域,随着接触载荷的增加,微动推迟进入混合区和滑移区,且混合区逐渐扩大;在相同的微动运行区域内,Ft/Fn系数随循环次数增加的变化趋势受接触载荷的影响不大,但Ft/Fn系数随着法向接触载荷的增加依次降低;在其它参量不变的情况下,接触载荷越大,微动更趋向于受扭动微动分量控制,表面损伤伴随着明显的剥落。扭转复合微动的磨损机制主要为磨粒磨损、氧化磨损和剥层。

On an advanced dual-rotary fretting rig,the dual-rotary fretting(DRF) wear behavior of 7075 Al alloy flat against GCr15 steel ball was investigated with various contact loads.Thus,the effect of contact load on the DRF wear behavior was examined.Based on the analysis of the frictional kinetics and the observation of wear morphologies,the damage characteristics of 7075 Al alloy were discussed in detail.The results show that the fretting regimes change with the variation of the contact load,the gross slip regime and mixed fretting regime of dual-rotary fretting are postponed,and the mixed fretting regime is broadened slowly.Under the same fretting regime,the Ft/Fn presents a same trend of evolution with the increase of the cycles,while the effect is insignificant with the increase of contact load.The value of Ft/Fn decreases with the increase of the contact load.With the increase of the contact load,the fretting is more approachable to control by torsional fretting component under a higher contact load,obviously accompanies with detachment.The wear mechanisms of DRF are mainly abrasive wear,oxidative wear and delamination.