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通过光学显微镜、场发射扫描电镜、X射线衍射(XRD)、硬度测试及拉伸试验等手段,研究了球化处理时间对AZ80析出相β-Mg17Al12及力学性能的影响。结果表明,铸态AZ80合金经退火处理后,晶间粗大的网状共晶β相消失,得到细小层片状脱溶β相均匀分布于α-Mg基体中。随球化时间延长,层片状β相开始溶断,先出现短棒状,然后向球状过渡,球化16h时镁基体上弥散分布大量细小颗粒状β相。继续延长时间,颗粒状β相出现溶解,数量减少,合金的综合性能最佳,屈服强度、抗拉强度和伸长率分别是132.5 MPa、252.4 MPa和9.56%。合金硬度随球化时间延长呈先升后降的变化规律,且均高于铸态合金。
The effects of spheroidizing treatment time on the microstructure and mechanical properties of AZ80 precipitation phase β-Mg17Al12 were investigated by optical microscopy, field emission scanning electron microscopy, X-ray diffraction (XRD), hardness test and tensile test. The results show that, the as-cast AZ80 alloy is annealed, the coarse intergranular eutectic β phase disappears, and the fine lamellar desoluble β phase is uniformly distributed in the α-Mg matrix. As the balling time prolonged, the lamellar β phase began to dissolve, the first appeared short rods, and then to the spherical transition, the ball of magnesium matrix 16h dispersed a large number of fine granular β phase. When extended for a long time, the granular β phase appeared to dissolve and the quantity decreased. The alloy had the best comprehensive properties. The yield strength, tensile strength and elongation were 132.5 MPa, 252.4 MPa and 9.56% respectively. The hardness of the alloy increases first and then decreases with the balling time, both of which are higher than that of as-cast alloy.