A356铝合金微弧氧化膜微动磨损行为的研究

Study of Fretting Wear Behavior of Microarc Oxidation film on A356 aluminum alloy

摘要:

采用微弧氧化（MAO）在A356铝合金表面制备MAO膜，利用球-平面接触在SRV-V微动摩擦磨损机上探究变载荷和位移下微弧氧化对A356微动磨损机理的影响。结果表明：MAO膜由疏松层和致密层构成，其均匀性、致密性和结合力良好。MAO膜的摩擦系数、磨损率均低于A356，MAO膜减摩耐磨性较好。随位移增加MAO膜的摩擦耗散能系数低于A356，MAO膜能提升A356微动磨损过程的稳定性。载荷增加时A356磨损机制为磨粒磨损-粘着磨损，伴随犁削和疲劳剥层； MAO膜磨损机制为磨粒磨损-粘着磨损和疲劳剥落。位移增加时A356磨损机制为粘着磨损和疲劳剥落，伴随微犁削；MAO膜磨损机制为粘着磨损和疲劳剥层-粘着磨损和磨粒磨损。A356的磨痕内聚集Fe、O元素，存在材料转移和氧化磨损；MAO膜磨痕内聚集Fe元素，存在材料转移。

Abstract:

The micro-arc oxidation ceramic film with wear resistance was prepared on the surface of A356 aluminum alloy using micro-arc oxidation technology (MAO). The investigation of the effect of micro-arc oxidation on the fretting wear mechanism of A356 aluminum alloy was explored on an SRV-V fretting friction and wear testing machine using sphere-plane point contact under variable normal loads and displacement amplitudes. The results show that the MAO film consists of a porous outer layer and a dense inner layer with good homogeneity, denseness and bonding strength. The friction coefficient and wear rate of MAO film are lower than those of A356 alloy when the normal load and displacement amplitude increases. It indicates that the MAO film has good friction reduction and wear resistance. The frictional dissipation energy coefficient of MAO film is lower than that of A356 alloy when the displacement amplitude increases, which can enhance the wear stability of fretting wear process of A356 aluminum alloy. The wear mechanism of A356 alloy changes from abrasive wear to adhesive wear when the normal load increases, accompanied by ploughing and fatigue peeling. The wear mechanism of MAO film changes from abrasive wear to adhesive wear and fatigue peeling when the normal load increases. The wear mechanism of A356 alloy changes from adhesive wear and fatigue peeling to adhesive wear and abrasive wear when displacement amplitude increases. The wear mechanism of MAO film changes from adhesive wear and fatigue peeling to adhesive wear and abrasive wear when displacement amplitude increases. The accumulated Fe and O elements are gathered within the A356 aluminum alloy wear scars, which indicates that there is material transfer and oxidation wear during the fretting wear process of GCr15/A356 frictional counterpart. The Fe elements are gathered within the MAO film wear scars, which indicates that there is material transfer of GCr15/MAO film frictional counterpart.