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研究了经超长时效处理后7075铝合金的力学性能、显微组织及摩擦学性能。结果表明:7075铝合金的硬度及强度具有双峰时效的特征,两个峰时效样品的硬度和拉伸强度相差不大,但伸长率有一定区别。与未经热处理的样品相比,时效处理后样品尽管摩擦系数较大,但摩擦系数随载荷的变化较小。随载荷增加,不同模式处理的铝合金均出现了从轻微磨损向严重磨损的转变,但经时效处理后样品磨损率明显小于未经热处理的样品,且第二峰样品的磨损率较小。时效处理后样品出现由轻微磨损向严重磨损转变的临界载荷显著提高,且第二峰样品临界载荷明显高于第一峰样品,表现出更优异的摩擦学性能;这可能归结于第二峰时效时合金组织中析出了数量更多、分布更均匀、颗粒更细小的强化相η’(MgZn2)的缘故。不同模式处理的铝合金磨损机制相近:在轻微磨损时以磨粒磨损和氧化磨损为主,严重磨损时以粘着磨损和剥层磨损为主。
The mechanical properties, microstructure and tribological properties of the 7075 aluminum alloy after being treated with a long aging treatment were studied. The results show that the hardness and strength of 7075 aluminum alloy have the characteristics of bimodal aging. The hardness and tensile strength of 7075 aluminum alloy have little difference but the elongation are different. Compared with the non-heat-treated samples, the samples with aging treatment showed smaller changes with the load, though the friction coefficients were larger. With the increase of load, the aluminum alloys treated with different modes all showed the transition from slight wear to severe wear. However, the wear rate of the samples after aging treatment was obviously less than that of the non-heat treated samples, and the wear rate of the second peak samples was smaller. The critical load of specimen after aging treatment changed from slight wear to severe wear remarkably, and the critical load of the second peak sample was obviously higher than the first peak sample, which showed more excellent tribological properties; this may be attributed to the second peak aging When the amount of alloy precipitation more uniform, more evenly distributed, smaller particles of the strengthening phase η ’(MgZn2) sake. The wear mechanism of aluminum alloy treated by different modes is similar: abrasive wear and oxidation wear are the main ones when slight wear, adhesive wear and peeling wear are the main wear when severe wear.