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主要研究了挤压前的时效处理工艺对AZ80镁合金显微组织和力学性能的影响,同时利用扫描电子显微镜对试样断口进行分析。结果表明:挤压前时效处理可以明显细化晶粒;时效过程中析出的Mg_(17)Al_(12)粒子弥散分布在晶界处,在动态再结晶过程中起到阻碍晶界移动、阻止晶粒长大、细化组织的作用;随着时效时间的延长或者时效温度的升高,晶粒细化效果减弱;对时效后合金进行挤压,试样的屈服强度、抗拉强度和延伸率均提高。通过对断口形貌的分析发现,早期裂纹产生于晶界处粗大的第二相周围,导致了拉伸过程中延伸率的下降。挤压前时效处理对AZ80的强化效果为高性能镁合金的设计和开发提供了一种全新的思路。
The effects of pre-extrusion aging treatment on the microstructure and mechanical properties of AZ80 magnesium alloy were studied. At the same time, the fracture surface of the AZ80 magnesium alloy was analyzed by scanning electron microscopy. The results show that the pre-extrusion aging treatment can significantly refine the grains. The precipitated Mg_ (17) Al_ (12) particles disperse in the grain boundaries during aging and prevent the grain boundaries from moving during the dynamic recrystallization Grain growth, refinement of the role of the organization; with the aging time or aging temperature, the grain refinement effect weakened; aging after the alloy extrusion, the sample yield strength, tensile strength and elongation Rates are increased. Through the analysis of the fracture surface morphology, it is found that the early cracks are generated around the coarse second phase at the grain boundary, resulting in the decrease of the elongation during the drawing process. The strengthening effect of AZ80 before extrusion treatment provides a new idea for the design and development of high performance magnesium alloy.