准晶对AZ91微观组织及摩擦磨损性能的影响

采用普通铸造法制备含高体积分数准晶相的Mg-Zn-Y(MZY)准晶中间合金。经SEM,EDS、XRD检测和摩擦磨损试验,研究MZY准晶颗粒加入量对AZ91基体合金微观组织及耐磨性能的影响。结果表明:MZY准晶颗粒可以明显细化AZ91合金的铸态组织,且骨骼状连续网状分布的β-Mg17Al12相断裂为弥散的岛状,合金的铸态组织中除α-Mg相、β-Mg17Al12相外还出现弥散分布在晶界处的高温稳定的Mg3Zn6Y准晶相;在不同载荷条件下,添加质量分数为6%的MZY准晶合金试样的摩擦因数由0.68减小至0.26,在100 N载荷下干摩擦30 min,其质量磨损量仅为基体合金质量的46.2%,磨损机理由基体的黏着摩擦转变为磨粒摩擦。

Effect of Magesium-Based Quasicrystal Addition on the Microstructure and Wear Properties of AZ91Magnesium Alloy

MZY quasicrystal master alloy was prepared under convetional casting conditions,and the microstructure and wear properties of AZ91 alloys with adding different additions of MZY quasicrystal master alloy were investigated by XRD,SEM,EDS and friction-wear tests etc.The results show that after adding MZY quasicrystal master alloy,the microstructure of matrix alloy has been obviously refined,and the morphology of β-Mg17Al12 phase changes from continuous nets to discontinuous nets or even to particles;For the addition of MZY quasicrystal alloy into AZ91 alloy,the Mg3Zn6Y quasicrystal phase dispersively distributes on the grain boundaries;Under different load conditions,the friction coefficient of the samples with 6% MZY quasicrystal alloy decreases from 0.68 to 0.26,and their mass wear is only 46.2% of the matrix alloy’s under 100 N load in 30 min dry friction.The wear properties are obviously improved,and the friction mechanism changes from conglutination abrasion to grain abrasion with increasing of MZY quasicrtstal alloy.