The Study Of Mg-Zn-Y-Zr Alloys' Microstructure And Properties

Dynamic recrystallization of MB25-F, MB25-E, MB22 Mg alloys were observed during hot extrusion or hot forging, and after DRX grains were fined. The average grain size is about 10μm, and some were fined less than 5μm. The structural refinement of MB25-E alloy was implemented by the transition of fibrous-to-coaxial during the recrystallization annealing at elevated temperature of 350oC, and after that the average grain size was about 5μm. During the T4 treatment, the plasticity increases greatly but the strength decreases. The strength and the plasticity of the three alloys increased after the T5 treatment, and the σb of MB25-F, MB25-E and MB22 was respectively up to 293MPa, 350Mpa and 279Mpa. After T6 treatment, the strength and the plasticity of the three alloys were increased markedly, especially of the plasticity. And the δ of the MB25-F, MB25-E and MB22 was respectively up to 20.4%, 20.2% and 28%. During the elevated temperature tensile, the δ of MB25-E represented highly and could be up to 95% at 250℃,but the δ of MB22 was only up to 31.6%.