热处理工艺对AZ61镁合金干摩擦磨损性能的影响

通过常温下的销盘式干滑动摩擦磨损试验,研究固溶及不同时间的时效处理对铸态AZ61镁合金摩擦磨损性能的影响.试验载荷为100 N,滑动速度为0.78 m/s,滑动距离为1 km.结果表明:固溶处理使铸态合金中的粗大β-Mg17Al12相溶解,导致合金的硬度降低,摩擦系数和磨损率升高;在170℃下对AZ61合金进行不同时间(0~80 h)的时效处理使尺寸细小的β相在晶内和晶界处析出,提高了合金的耐磨性,其中时效20 h后合金的摩擦系数和磨损率最低.AZ61合金在摩擦磨损的过程中共存在三种磨损机制:磨粒磨损、氧化磨损及剥层磨损.

Effects of Heat Treatment on Dry Wear Properties of AZ61 Magnesium Alloy

The effects of solution treatment and the aging time of its succeeding aging process on dry wear property of AZ61 magnesium alloys were investigated by using a pin-on-disc apparatus. Wearing rate and friction coefficient were measured under the load of 100 N， sliding speed of 0.78m/s and sliding distance of 1km. The results showed that the coarsen β-phases (Mg₁₇Al₁₂) were dissolved after solution treatment， resulted in the decrease of the hardness of the alloy. The friction coefficient and wearing rate of the alloy increased significantly after solution treatment. Moreover， the AZ61 alloy exhibited a better wear resistance after aging at the temperature of 170℃ with an aging time ranging from 0 to 80h， owing to precipitate large amount of the fine Mg₁₇Al₁₂ phases distributed in the α-Mg matrix.The friction coefficient and wearing rate were the lowest when the aging time was about 20h.Three wearing mechanisms in AZ61 alloys were observed as follows: abrasion， oxidation and delamination.