Microstructure, texture and mechanical properties of Mg-8Gd-4Y-1Nd-0.5Zr alloy prepared by pre-deformation annealing, hot compression and ageing

An extruded Mg-8Gd-4Y-1Nd-0.5Zr alloy was pre-heated at 470 degrees C for 1 h and subsequently compressed at 470 degrees C and two strain rates of 0.2 and 0.0003 s(-1). Microstructure, texture and mechanical properties of the alloy were examined by optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), hardness test and tensile test. The results show that the post-deformed microstructures of alloy are non-uniform at both strain rates due to the dissolution of RE-rich particles and the occurrence of DRX. The textures of post-deformed alloy are affected by strain rate. The alloy exhibits a strong basal texture of < 0001 >//ND (normal direction) after compression at 0.2 s(-1), while a weak texture component of < 0001 >//ED (extrusion direction) is formed in the compression obtained at 0.0003 s(-1). Compared with the alloy compressed at 0.0003 s(-1), the compressed alloy obtained at 0.2 s(-1) presents better comprehensive mechanical properties with the ultimate tensile strength of 426 MPa, yield strength of 345 MPa and ductility of 2.1% when being aged at 225 degrees C for 8 h.