Acta Metallurgica Sinica (English Letters) ›› 2023, Vol. 36 ›› Issue (3): 469-485.DOI: 10.1007/s40195-022-01482-8

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Hot Compression Mechanical Behavior of Solution Heat-Treated and Pre-aged Mg-Zn-Gd-Er Alloys

Bo Che1, Liwei Lu1(), Longfei Liu1, Yan Yang2(), Wei Kang1, Jun Luo3(), Zhiqiang Wu1, Yongfeng Qiu4,5   

  1. 1School of Materials Science and Engineering, Hunan University of Science and Technology, Xiangtan 411201, China
    2College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China
    3Hunan Provincial Key Laboratory of Vehicle Power and Transmission System, Hunan Institute of Engineering, Xiangtan 411104, China
    4Guiyang Aluminum Magnesium Design & Research Institute Co., Ltd, Guiyang 550081, China 5 School of Automation, Central South University, Changsha 410083, China

Abstract:

The mechanical behavior of solution heat-treated and pre-aged Mg-6Zn-1Gd-1Er alloys during hot compression (from 180 to 330 °C) has been investigated. The results showed that the flow stress curves of the pre-aged sample (PAS) intersected with that of the solution heat-treated sample (SHTS) during hot compression. At 180 °C, when the true strain is 0.27 and 0.47, the PAS showed larger and smaller stress (210.80 MPa vs. 207.58 MPa and 205.67 MPa vs. 207.93 MPa) than the SHTS, respectively. These phenomena were due to the stronger interaction of W phase and dislocations/twins under the strain of 0.27, while dynamic recrystallization softening occurred under the strain of 0.47. When the temperature increased to 330 °C, the flow stress of PAS and SHTS showed an opposite trend to that of 180 °C. Continuous dynamic recrystallization and particle stimulated nucleation based on slip operations are the main deformation mechanisms under 330 °C. At the true strain is 0.33 and 0.53, the PAS has smaller and larger stress (61.32 MPa vs. 63.69 MPa and 58.75 MPa vs. 57.09 MPa) than the SHTS, respectively. The increasing deformation resistance of dynamic precipitation improved the flow stress under smaller strain and dynamic recrystallization decreased the flow stress under high strain, which resulted the opposite phenomena of SHTS.

Key words: Mg-6Zn-1Gd-1Er alloy, Mechanical behavior, Precipitates, Twin, Dynamic recrystallization