A high-performance Mg-4.9Gd-3.2Y-1.1Zn-0.5Zr alloy via multidirectional forging after analyzing its compression behavior

A high-performance Mg-4.9Gd-3.2Y-1.1Zn-0.5 Zr alloy has been fabricated by multidirectional forging (MDF) after analyzing its compression behavior. The as-homogenized alloy exhibits a high activation energy Q of deformation (similar to 285 kJ/mol). The size of DRXed grains after compression tends to decrease as the Z-H parameter (Z) increases, showing a grain size exponent m of similar to 4.0. Lamellar LPSO phases, kinking deformation, and bimodal microstructure are detected at the relatively low compression temperature of 350 and 400 degrees C, while sufficient DRX can be achieved at 500 degrees C, accompanied by the dissolution of lamellar LPSO. According to the processing maps, MDF was successfully conducted under an appropriate condition. After peak-aged at 200 degrees C for 78 h, the MDFed billet exhibits a tensile yield strength (TYS) of 331 and 305 MPa at room temperature and 200 degrees C, respectively. The high strength mainly results from the combination of fine grains, low Schmid factor for basal slip, sufficient beta' ageing precipitates, and directionally arranged interdendritic LPSO phases, etc. This paper provides a feasible way for the fabrication of high-performance, low-RE-content, and large-scale Mg components for industrial production. (C) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

A high-performance Mg-4.9Gd-3.2Y-1.1Zn-0.5Zr alloy was successfully fabricated by multidirectional forging (MDF), exhibiting high activation energy for deformation and fine grains with satisfactory mechanical properties achieved through dynamic recrystallization (DRX) at lower temperatures. The alloy displayed excellent tensile yield strength and promising potential for industrial production of high-performance, low rare earth content, and large-scale Mg components.