J. Mater. Sci. Technol. ›› 2018, Vol. 34 ›› Issue (7): 1061-1066.DOI: 10.1016/j.jmst.2018.01.017

Special Issue: High Strength Alloys-2018

• Orginal Article •     Next Articles

Insight from in situ microscopy into which precipitate morphology can enable high strength in magnesium alloys

Bo-Yu Liua, Nan Yanga, Jian Wangb, Matthew Barnettc, Yun-Chang Xind, Di Wue, Ren-Long Xind, Bin Lif, R.Lakshmi Narayanag, Jian-Feng Nieh, Ju Liah, Evan Maaj(), Zhi-Wei Shana()   

  1. a Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano) & Hysitron Applied Research Center in China (HARCC), State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, People’s Republic of China
    b Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
    cInstitute for Frontier Materials, Deakin University, Geelong, Victoria 3216, Australia
    dCollege of Materials Science and Engineering, Chongqing University, Chongqing 400045, People’s Republic of China
    eInstitute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, People’s Republic of China
    fDepartment of Chemical and Materials Engineering, University of Nevada, Reno, USA
    gDepartment of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
    hDepartment of Materials Science and Engineering, Monash University, Melbourne, Victoria 3800, Australia
    iDepartment of Nuclear Science and Engineering and Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
    jDepartment of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
  • Received:2018-01-02 Revised:2018-01-12 Accepted:2018-01-18 Online:2018-07-10 Published:2018-07-22

Abstract:

Magnesium alloys, while boasting light weight, suffer from a major drawback in their relatively low strength. Identifying the microstructural features that are most effective in strengthening is therefore a pressing challenge. Deformation twinning often mediates plastic yielding in magnesium alloys. Unfortunately, due to the complexity involved in the twinning mechanism and twin-precipitate interactions, the optimal precipitate morphology that can best impede twinning has yet to be singled out. Based on the understanding of twinning mechanism in magnesium alloys, here we propose that the lamellar precipitates or the network of plate-shaped precipitates are most effective in suppressing deformation twinning. This has been verified through quantitative in situ tests inside a transmission electron microscope on a series of magnesium alloys containing precipitates with different morphology. The insight gained is expected to have general implications for strengthening strategies and alloy design.

Key words: Precipitate selection criterion, In-situ TEM, Mg alloy, Mechanical property, Deformation twinning