J. Mater. Sci. Technol. ›› 2021, Vol. 73: 66-75.DOI: 10.1016/j.jmst.2020.09.020

• Research Article • Previous Articles     Next Articles

Effect of forced-air cooling on the microstructure and age-hardening response of extruded Mg-Gd-Y-Zn-Zr alloy full with LPSO lamella

S.Z. Wua, T. Nakatab, G.Z. Tanga, C. Xua,b,*(), X.J. Wanga, X.W. Lic,**(), X.G. Qiaoa, M.Y. Zhenga, L. Genga, S. Kamadob, G.H. Fand   

  1. aSchool of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
    bResearch Center for Advanced Magnesium Technology, Nagaoka University of Technology, Nagaoka 940-2188, Japan
    cSchool of Material Science and Engineering, Harbin University of Science and Technology, Harbin 150040, China
    dKey Laboratory for Light-weight Materials, Nanjing Tech University, Nanjing 211816, China
  • Received:2020-07-17 Revised:2020-09-06 Accepted:2020-09-13 Published:2021-05-20 Online:2020-09-30
  • Contact: C. Xu,X.W. Li
  • About author:**E-mail addresses: lixuewen2000@163.com (X.W. Li).
    *School of Materials Science and Engineering, HarbinInstitute of Technology, Harbin 150001, China.cxu@hit.edu.cn (C. Xu),

Abstract:

The homogenized Mg-8.2Gd-3.8Y-1.0Zn-0.4 Zr (wt.%) alloy full of plate-shaped long period stacking ordered (LPSO) phases was hot extruded in the atmosphere and cooled by the forced-air, then the effect of forced-air cooling on the microstructure and age-hardening response of the alloy was investigated in this work. The results show that in comparison with the extruded sample cooling in the atmosphere, the forced-air cooling restricts dynamic recrystallization (DRX) and brings about finer dynamic recrystallized (DRXed) grain size, stronger basal texture and higher dislocation density. Furthermore, the forced-air cooling promotes the dynamic precipitation in the DRXed regions and facilitates formation of plate-shaped LPSO phases and γ′ phases with smaller interspacing in the unrecrystallized (unDRXed) regions, then slightly restricts the precipitation of β′ phases during aging. After peak-ageing treatment, the extruded sample with forced-air cooling shows superior tensile properties with a tensile yield strength of 439 MPa, an ultimate tensile strength of 493 MPa, and elongation to failure of 18.6 %.

Key words: Mg-RE alloy, LPSO phase, Dynamic recrystallization, Precipitation, Mechanical properties