Study On The Microstructure And Mechanical Properties Of Magnesium Alloy By Equal Channel Angular Extrusion

Magnesium alloys have high potential as structural materials for aerospace and other transport applications due to their high specific properties, low density and high damping capacity. However, magnesium alloys have poor formability and limited ductility at room temperature ascribed to their hexagonal close-packed (HCP) crystal structure. Grain refinement is an important practice to improve the mechanical properties of magnesium alloy, while equal channel angular extrusion (ECAE) provides a technique for producing ultra-fine grain sizes in the submicrometer or nanometer range in bulk materials. In recent years, the microstructure and tensile properties of ECAE AZ31 Mg alloy were studied, and following common results were obtained as that the grains were refined effectively, the elongation was improved but the yield stress decreased after ECAE, which indicated that it is difficult to improve both the strength and the ductility of the ECAE Mg alloy though the grain size can be refined significantly by ECAE processing. Moreover, there is still neither a detailed description of microstructure evolution for Mg-Al-Zn magnesium alloy during ECAE, nor a clear understanding of their deformation mechanism at room temperature after ECAE.The purpose of this paper is to investigate the microstructure evolution and mechanical properties of Mg-Al-Zn magnesium alloy by ECAE, and place an emphasis on the understanding of grain refinement mechanism during ECAE, the deformation and...