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研究了热处理对AS41镁合金显微组织、力学和摩擦学性能的影响。结果表明:热处理前后AS41镁合金物相组成未发生改变,均由基体相(α-Mg)和β-Mg17Al12及Mg2Si相构成,其中β-Mg17Al12相和Mg2Si相为合金的强化相;但铸态时以粗大的网状不连续分布于晶界的β-Mg17Al12相在热处理后以细小的颗粒状在晶界和晶内弥散分布;汉字状Mg2Si相尺寸减小,且部分形成颗粒状组织。在优化的热处理工艺下,AS41镁合金的抗拉强度和屈服强度分别提高了22.1%和25.7%,而伸长率受热处理的影响较小。在低载荷时,热处理后的AS41镁合金较铸态镁合金具有更低和更稳定的摩擦系数;在较高载荷时,热处理的镁合金具有更优异的耐磨性能。铸态镁合金在较高载荷下的磨损机理为剥层磨损和磨粒磨损,而热处理后的镁合金磨损机理主要为氧化磨损和磨粒磨损;热处理前后材料显微组织变化是导致磨损机理变化的主要原因。
The effects of heat treatment on the microstructure, mechanical properties and tribological properties of AS41 magnesium alloy were studied. The results show that the phase composition of AS41 magnesium alloy does not change before and after heat treatment. Both phases consist of matrix phase (α-Mg), β-Mg17Al12 and Mg2Si phase, and β-Mg17Al12 phase and Mg2Si phase are the strengthening phases. However, The β-Mg17Al12 phase, which is discontinuously distributed in the grain boundaries with coarse meshes, is diffused and distributed in the grain boundaries and in the grain after the heat treatment. The shape of the Chinese character Mg2Si decreases and some of them form granular structures. Under the optimized heat treatment process, the tensile strength and yield strength of AS41 magnesium alloy increased by 22.1% and 25.7% respectively, while the elongation was less affected by heat treatment. At low load, the heat treated AS41 magnesium alloy has a lower and more stable friction coefficient than the as-cast magnesium alloy; the heat treated magnesium alloy has more excellent wear resistance at higher loads. The wear mechanism of as-cast magnesium alloy under high load is peel wear and abrasive wear, while the wear mechanism of magnesium alloy after heat treatment is mainly oxidative wear and abrasive wear. The microstructure changes before and after heat treatment lead to the change of wear mechanism The main reason.