热处理工艺对低温挤压Zn-15Al锌合金组织及性能的影响

采用拉伸试验和扫描电镜分析技术手段,研究了不同冷却速度对200℃挤压Zn-15Al锌合金的微观组织和室温力学性能的影响.结果表明:经320℃处理1 h后,变形态细小的α(Al)相发生了粗化.经水淬后α(Al)相发生了连续析出,形成了α(Al)+η(Zn)细小的粒状组织,使其强度稍有提高,塑性明显降低.而经空冷后α(Al)相发生了共析分解,形成了细片层状组织,导致其强度提高约1倍,塑性下降约80%.这意味着能够通过热处理工艺来调整变形态Zn-15Al锌合金的力学性能,以满足不同应用领域的要求.

Effects of heat treatment on microstructure and mechanical property of extruded Zn-15 Al Zn alloy at lower extrusion temperature

The influences of cooling rates during heat treatment on the microstructure and mechanical properties of the extruded Zn-15Al Zn-alloy at 200 ℃ have been investigated by tensile test and scanning electron microscopy. The results show that the fine α( Al)phase of extruded Zn -15Al Zn -alloy at 200 ℃ occurred coarsening by heated treatment at 320 ℃ for 1 h. The tensile strength of extruded Zn -15Al Zn - alloy increased slightly,while the elongation of extruded Zn-15Al Zn-alloy decreased significantly after water quenching,because theα(Al)phase is transformed into α( Al)+η( Zn)fine granular structure though continuous precipitation. After air cooling,the tensile strengthen were increased by about 1 times and the elongation decreased by about 80%,Owing to the α( Al)phase formed a fine lamellar structure decomposition by eutectoid transformation. It is implied that the different mechanical properties can be obtained in the extrusion Zn-15Al Zn alloy manufactured by heat treatment,and the mechanical properties can be satisfied the requirements of different applications.