J. Mater. Sci. Technol. ›› 2019, Vol. 35 ›› Issue (11): 2423-2429.DOI: 10.1016/j.jmst.2019.06.008

• Orginal Article •     Next Articles

Deformation and fracture mechanisms of an annealing-tailored “bimodal” grain-structured Mg alloy

Baojie Wanga, Daokui Xubd*(), Liyuan Shengc**(), Enhou Hanbd, Jie Suna   

  1. aSchool of Environmental and Chemical Engineering, Shenyang Ligong University, Shenyang, 110159, China
    bKey Laboratory of Nuclear Materials and Safety Assessment, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
    cPeking University, Shenzhen Institute, Shenzhen Key Lab Human Tissue Regenerate & Repair, Shenzhen, 518057, China;
    dEnvironmental Corrosion Center, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
  • Received:2019-05-17 Revised:2019-06-11 Accepted:2019-06-13 Online:2019-11-05 Published:2019-10-21
  • Contact: Xu Daokui,Sheng Liyuan

Abstract:

Through investigating and comparing the mechanical behavior of an as-rolled Mg-3%Al-1%Zn (wt%) alloy before and after annealing treatments, it was revealed that the formation of annealing-tailored bimodal grain structure ensured the 330 °C/4 h samples having a good combination of tensile strength and plasticity. Failure analysis demonstrated that for the as-rolled and 330 °C/1 h samples with fine grain structure, their plastic deformation was mainly attributed to basal slips, whereas the deformation mechanism in the bimodal grain-structured samples was dominated by basal slips in fine grains and twinning in coarse grains. For the 330 °C/8 h samples with coarse grain structure, high densities of twins were activated. Meanwhile, basal slips occurred in the twinned and un-twinned areas of coarse grains and could pass through twin boundaries. For differently treated samples, cracking preferentially occurred along slip bands, resulting in their transgranular fractures.

Key words: Mg alloy, Grain structure, Deformation mechanism, Cracking, Fracture