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

摘要

A high-performance Mg-4.9Gd-3.2Y-1.1Zn-0.5Zr 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(~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~4.0.Lamellar LPSO phases,kinking deformation,and bimodal microstructure are detected at the relatively low compression temperature of 350 and 400℃,while sufficient DRX can be achieved at 500℃,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℃for 78 h,the MDFed billet exhibits a tensile yield strength(TYS)of 331 and 305 MPa at room temperature and 200℃,respectively.The high strength mainly results from the combination of fine grains,low Schmid factor for basal slip,sufficientβ’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.