Improved mechanical properties of Mg-3Al-1Zn alloy sheets by optimizing the extrusion die angles: Microstructural and texture evolution

Mg-3Al-1Zn (AZ31) alloy sheets fabricated using extrusion dies with angles of 30 degrees, 45 degrees, 60 degrees and 90 degrees were investigated. Finite element method was used to analyze the effective strain distribution in AZ31 Mg alloy during extrusion. The microstructure, texture and final mechanical properties were determined and compared among various extruded AZ31 sheets. Results demonstrated that the difference of effective strain was introduced during extrusion due to the variation in die angles. In the case of the 45 degrees extrusion die, a large difference in effective strain along normal direction could form during sheet forming, which resulted in a uniform microstructure and weak basal texture of extruded AZ31 sheet. Therefore, the sheet processed using 45 degrees extrusion die showed lower yield strength and r-value, but higher ductility and n value. This study suggested that optimization of extrusion die angle could be an effective method to improve the mechanical properties of AZ31 Mg alloy sheets. (C) 2018 Elsevier B.V. All rights reserved.