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

• DOI: 10.1016/j.jmst.2020.08.054
• Publication Date: 2020-09-15T02:26:19Z
• Authors: Xiaojie Zhou; Yuan Yao; Jian Zhang; Xiaomin Chen; Weiying Huang; Jing Pan; Haoran Wang; Maopeng Weng
• Keywords: 02 engineering and technology; 0210 nano-technology

Abstract 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 (∼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 °C, while sufficient DRX can be achieved at 500 °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 °C for 78 h, the MDFed billet exhibits a tensile yield strength (TYS) of 331 and 305 MPa at room temperature and 200 °C, respectively. The high strength mainly results from the combination of fine grains, low Schmid factor for basal slip, sufficient β ' 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.