固溶时效对半固态挤压SiC/AZ91D组织与性能的影响

Effects of solution and aging treatment on the microstructure and properties of semi-solid extruded SiC/AZ91D

摘要:

在本次实验研究中，为了获得综合力学性能良好的镁基复合材料，采用近液相线保温法制备10μm 15wt.% SiC/AZ91D半固态坯料进行半固态挤压后得到其复合材料，再经过415℃固溶处理24 h (T4)和进一步220℃时效处理8h (T6)。结果表明，随着固溶时效的进行，晶界处的Mg17Al12相溶解，然后在晶粒中二次析出，并逐渐球化。与T6处理前的15wt.% SiC/AZ91D复合材料相比，经T6处理后其具有良好的综合力学性能，拉伸强度、屈服强度、伸长率和硬度分别达到242MPa、204MPa、2.3%和132.26HV。

Abstract:

In the present work, in order to obtain the magnesium matrix composites with good mechanical properties, the semi-solid billet 10μm 15wt.%SiC/AZ91D was prepared using the near-liquidus heat-holding method and later semi-solid extruded to get the magnesium matrix composites. Next, 24h of solution treatment at 415oC (T4) was conducted, followed by 8h of further aging treatment at 220oC (T6). The results show that, with the progress of solution and aging treatments, Mg17Al12 phases at the grain boundary were dissolved, and secondary-precipitated in grains with layered and spheroidized gradually. The magnesium matrix composites 15wt.% SiC/AZ91D after T6 treatment showed better integrated mechanical properties when compared with those before, with tensile strength, yield strength, elongation, and hardness reaching 242MPa, 204MPa, 2.3% and 132.26HV, respectively.