Study On Microstructures And Mechanical Properties Of Rolled Mg-Zn-Ce-Zr(MN) Alloys

The microstructures and mechanical properties of rolled Mg-0.5Zn-0.5Ce-0.5Zr(1.0Mn) alloys were investigated. The alloys were rolled by different per-pass reductions (20%, 30%, 50%) at temperature of 400℃and 450℃with a run speed of 10 m/min. The evolution of microstructure and texture were observed by OM, SEM,TEM,XRD and EBSD. Tensile test was also carried out at room temperature for analysis. The influence of microstructures on strength, elongation and anisotropy of Mg-0.5Zn-0.5Ce-0.5Zr(1.0Mn) alloy sheets has been studied. The results are given as following:Mg-0.5Zn-0.5Ce-0.5Zr(1.0Mn) alloy sheets had a good formability with almost no edge cracking after rolling at 450℃. But elevating the temperature would affect the surface quality of alloy sheets as peeling happened. For Mg-0.5Zn-0.5Ce-0.5Zr alloy, the results showed that only dynamic recovery (DRV) took place during rolling at 400℃with various per-pass reductions. Elevate the temperature to 450℃, continuous dynamic recrystallization occurred in Mg-0.5Zn-0.5Ce-0.5Zr alloy sheets. Meanwhile, more dislocations were found in 50% per-pass reduction rolled alloy. For Mg-0.5Ce-0.5Zn-1.0Mn alloy sheets rolled at 450℃, dynamic recrystallization occurred. The nucleation mechanism was attribute to twinning-induced nucleation, which led to a random distribution of new grain orientation.The main texture type of Mg-0.5Zn-0.5Ce-0.5Zr(1.0Mn) alloy sheets was {0001} basal texture. The overall texture intensity of it increased with increasing per-pass reduction at the same temperature,while decreased with increasing temperature. After annealing at 500℃, static recrystallization occurred in Mg-0.5Zn-0.5Ce-0.5Zr(1.0Mn) alloy sheets. Texture weakening also happened after annealing, this was attributed to grain rotation during static recrystallization. Dislocation pile in alloy sheets increased with increasing per-pass reduction, which providing a drive force to form more recrystallization grains, so that a fine microstructure after annealing.Obvious work hardening and anisotropy were found in rolled Mg-0.5Zn-0.5Ce-0.5Zr(1.0Mn) alloy sheets due to the deformation microstructures and the strong basal texture. After annealing at 500℃, static recrystallization occurred in Mg-0.5Zn-0.5Ce-0.5Zr(1.0Mn) alloy sheets, which lead to a good ductility, random texture as well as weak anisotropy.This paper also compared the resistance to corrosion of these two alloys, and results showed that alloys containing Mn had much better corrosion resistivity than alloys without Mn.