关键词: 材料实验, Mg-Y4-Nd3合金, T6处理, 沉淀强化, 抗拉强度, 摩擦磨损

Abstract: Microstructure, tensile properties and tribological properties of as cast and T6 treated Mg-Y4-Nd3 alloy (solution treatment for 8 h at 525 ℃ and aging treatment for 16 h at 250 ℃) were investigated. The results show that the eutectic phase in Mg-Y4-Nd3 alloy was distributed at the grain boundary of αMg solid solution in the form of discontinuous network. After solution and aging treatment, the microstructure of the alloy exhibited equiaxed grains and most of the eutectic phase dissolved into the α-Mg matrix. The precipitate phases dispersed uniformly after aging process. The tensile strength of the two alloys with different treatments decreased as the temperature was increased whereas the elongation increased. At the same temperature the alloy after T6 treatment shows higher tensile strength than the as cast alloy. As the applied load was increased, the friction coefficient of the T6 alloy decreased but the wear rate increased under the dry sliding condition. Moreover, the wear mechanism changed from abrasive wear and oxidation wear to delamination wear; at high load the worn surface shows plastic deformation and extrusion phenomenon.

Key words: Mg-Y4-Nd3 alloy, T6 treat, precipitation strengthening, tensile strength, friction and wear