时效处理对AA2099铝锂合金摩擦学行为的影响

研究了固溶及不同时效状态AA2099铝锂合金的力学性能、摩擦学行为及机理.结果表明:随时效时间的延长,摩擦系数先降低后升高,时效35 h时摩擦系数最低(0.137);磨损量单调减少,时效96 h合金的磨损率最低,为1.7×10–3 mm3/(N·m).固溶态和不同时效态的AA2099铝锂合金主要磨损机制均为磨粒磨损和黏着磨损.摩擦产物对摩擦系数有重要影响,时效35 h的合金摩擦产物分布均匀且连续,具有良好的减摩作用;合金的力学性能与磨痕浅层结构稳定性共同影响合金的磨损率,时效时间小于35 h,合金表面易形成发生剥落的结构,磨损量变化与传统认为的H/E变化不符,但随时效时间进一步延长,剥落减少,磨损量与H/E变化正相关.

Effect of Aging on Tribological Performance of AA2099 Aluminum-Lithium Alloy

The mechanical properties, tribological properties and wear mechanism of AA2099 Al-Li alloy under solution heat treatment(SHT) and different aging treatments were investigated. The results reveal that with prolonged aging time, the average friction coefficient decreased first and then increased, and the lowest friction coefficient emerged when alloy was aged for 35 h(0.137).; The wear rate monotonously decreased, the lowest value wasobtainedfromthesampleaged for 96 h 1.7×10^-3mm³/(N·m)]. The wear mechanism of AA2099 Al-Li alloy at solid solution and different aging state in dry condition was abrasive wear and adhesive wear. Friction products had important influence on the friction coefficient, and friction products distributed homogeneously and continuously for sample aged for 35 h, which had good anti-friction effect. Mechanical properties combined with the wear-shallow structure stability mutual influenced the wear rate, when aging time was less than 35 h. Severe delamination in the wear-shallow area was observed. Variation of wear rate was not associated with H/E. As long as the aging time was more than 35 h, spalling was reduced and wear rate was positively related to the H/E change.