新SIMA制备坯料触变挤压AZ61镁合金零件的组织与性能(英文)

新应变诱导熔化激活法被用来制备高质量的AZ61镁合金半固态坯料。利用光学显微镜和拉伸实验,研究触变挤压成形零件的微观组织与力学性能。结果表明:当施加的压力为784MPa,保压时间为90s,模具温度为450℃时,半固态坯料能够完全充填模具型腔。与半固态等温处理方法相比,新SIMA法制备的半固态坯料触变挤压成形零件的抗拉强度和伸长率分别为300.5MPa和22%;并且成形零件的微观组织晶粒细小、组织均匀。随着等温处理温度的升高和保温时间的延长,成形零件的抗拉强度和伸长率先增加后降低。当挤压道次从1增加至4时,成形零件的抗拉强度和伸长率明显增加。

Microstructure and mechanical properties of AZ61 magnesium alloy parts achieved by thixo-extruding semisolid billets prepared by new SIMA

New strain induced melt activation (new SIMA) method was employed to prepare high-quality semisolid billet of AZ61 magnesium alloy. Optical microscopy and tensile test were used to study the microstructure and mechanical properties of the thixo-extruded component. The results showed that the optimal process parameters for achieving the complete filling status involved the applied pressure of 784 MPa, the pressure holding time of 90 s and the die temperature of 450 °C. Compared to semisolid isothermal treatment, high mechanical properties such as the tensile strength of 300.5 MPa and elongation of 22% and fine microstructure were obtained in the thixo-extruded parts. With increasing the isothermal temperature and holding time, the tensile strength and elongation were increased firstly and then decreased. When the press pass was increased from 1 to 4, the tensile strength and elongation of the thixo-extruded parts were greatly enhanced and microstructure was refined obviously.