固溶时效对半固态挤压SiC/AZ91D组织与性能的影响

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 15%SiC/AZ91D(质量分数)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8 h(T6)。结果表明:随着固溶时效的进行,晶界处的层片状和点状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15%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(HV)分别达到242 MPa、204 MPa、2.3%和1322 MPa。

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

In order to obtain the magnesium matrix composites with good mechanical properties,the semi-solid 15 wt%SiC/AZ91 D billet with 10μm in length was prepared by the near-liquidus heat-holding method and later extruded to get the magnesium matrix composites.Solution treatment at 415℃for 24 h(T4)was conducted,followed by further aging treatment at 220℃for 8 h(T6).The results show that during the solution and aging treatments,Mg17Al12 phases at the grain boundary dissolve,and the secondary-precipitated phases appearing in grains become layered and spheroidized gradually.The magnesium matrix composites 15 wt%SiC/AZ91 D after T6 treatment show better integrated mechanical properties when compared with those of the composites before T6 treatment.The tensile strength,yield strength,elongation,and hardness reach 242 MPa,204 MPa,2.3%and 1322 MPa,respectively.