Effects of microstructure and texture evolution on strength improvement of an extruded mg-10gd-2y-0.5zn-0.3zr alloy

Abstract

The extrusion process with a large extrusion ratio (36:1) has a great effect on microstructure refinement and strength improvement of the Mg-10Gd-2Y-0.5Zn-0.3Zr alloy. The tensile yield strength, ultimate tensile strength, and elongation of the extruded alloy are 306MPa, 410MPa, and 16.3%, respectively. The causes of strength improvement of the extruded alloy are discussed in detail. The grain refinement is a main strengthening source, contributing ~67MPa to the tensile yield strength of the extruded alloy. Dense precipitation of long period stacking ordered (LPSO) and β′ phases on the matrix and transformation of texture type in the extrusion process also partly increase the strength. In addition, a small number of {1012} twins during tensile test is another factor improving the strength of the extruded alloy.