定向凝固纯铜组织性能研究

Microstructure and Property of Directional Solidification of Pure Copper

采用高真空多功能定向凝固及悬浮熔炼设备,以不同凝固速度制备纯铜试样,并对定向凝固纯铜试样的显微组织和机械性能进行了分析研究.通过实验获得了定向凝固纯铜的组织性能.当凝固速度小于500μm/min时,定向凝固的纯铜试样横、纵截面的晶粒形貌都是等轴晶,晶粒内存在孪晶,凝固速度较小时,其孪晶组织数量较多.当凝固速度大于500μm/min时,定向凝固的纯铜试样横截面的晶粒形貌是等轴晶,而纵截面的晶粒形貌是柱状晶,晶粒内基本不存在孪晶组织.定向凝固纯铜的室温机械性能是:当凝固速度在50μm/min的条件下,试样的抗拉强度约153 MPa,较普通铸造纯铜试样的低,而屈服强度约91.8 MPa,延伸率约80.12%,都优于普通铸造纯铜试样.透射电镜分析表明,纯铜定向凝固过程中形成的孪晶B=[110].

with high vacuum function directional solidification and suspension smelting equipment, the pure copper specimen was peoduced in directional solidification at different cooling rate. The microstructure has been studied. When solidafication speed is less than 500 tim/rain, equiaxed crystals appear in cross and longitudinal sections, there are some twins among crystals, the number is much more,while the solidification speed is smaller. When solidification speed is large than 500 μm/min, equiaxed crystals appear in cross section, colummar crystals in longitudinal section, there is no twins within crystals. At room temperature, the tensile strength of directional solidification pure copper with solidifacation speed of 50 μm/min is about 153 MPa less than that of ordinary casting pure copper specimen, yield strength is about 91.8 Mpa,extension rate is about 80. 12% better than that of ordinary casting pure copper specimen. The SEM shows：the twin plane is [110].