AS41耐热镁合金的摩擦学行为研究

Tribological characteristics of heat resistant magnesium alloy AS41

研究了AS41耐热镁合金在室温和200℃时的显微组织、力学和摩擦学性能,探讨了其在高温的摩擦学机制。研究表明:AS41镁合金主要由基体(α-Mg相)和第二相(Mg17Al12、Mg2Si和MgO相)组成,在200℃时除伸长率有所增加外,抗拉强度和屈服强度均较室温时显著下降。AS41镁合金的摩擦因数随载荷增大而减小,滑行速度和滑行距离对摩擦因数影响不大;磨损率随着载荷和滑行距离的增加而增大,但随滑行速度的增加而减小;AS41镁合金在200℃的摩擦学性能优于其室温的。随着载荷变化,磨损机制发生变化;低载荷时表现为氧化磨损和磨粒磨损;中等载荷时表现为磨粒磨损和轻微剥层磨损;较高载荷时表现为剥层磨损。

The microstructure, mechanical and tribological properties of heat resistant magnesium alloy AS41 under room temperature and 200℃ were studied,the wear mechanism of magnesium alloy under 200℃ was also discussed. The results showed that AS41 magnesium alloy consisted of matrix phase （α-Mg） and second phase（ Mg17Al12 ,Mg2Si and MgO） ,the elongation of magnesium alloy under 200℃ was larger than that under room temperature, however the ultimate strength and yield strength under 200℃ remarkably decreased comparing with those under room temperature. The friction coefficient in- creased with the increase of load, but the sliding velocity and distance had few influence on the friction coefficient; the wear rate increased with the increase of load and sliding distance, but decreased with the sliding velocity. Moreover, the tribological performances of the magnesium alloy under 200℃ were better than those under room temperature. The wear mechanisms were changed with the load ; it showed oxidation and abrasive wear at low load, abrasive and mild delamination wear at medium load; and delamination wear at high load.