Micromechanical origin of the enhanced ductility in twinless duplex Mg–Li alloy

Di Xie, Zongyang Lyu, Mingyu Fan, Huck Beng Chew, Peter K. Liaw, Hongbin Bei, Zhongwu Zhang, Yanfei Gao

Research output: Contribution to journalArticlepeer-review

Abstract

Unlike many Mg alloys that exhibit limited ductility, duplex Mg–Li alloys possess enhanced ductility but the underlying mechanisms are unclear. Using real-time in situ neutron diffraction measurements, we show that the underlying deformation modes in this duplex microstructure include an early yield of body-centered-cubic (BCC) β-Li phase and the later elevated hardening in this phase at large macroscopic plastic strain, and the sequential activation of basal and pyramidal <a> slip systems in hexagonal-close-packed (HCP) α-Mg phase. The latter relieves the Mises constraint for deformation compatibility, and the successive yielding sequence promotes the overall work hardening rate, both of which are beneficial for ductility enhancement. No obvious twinning activities were found and correspondingly the hysteresis loops were symmetric upon a full loading cycle within ±1% applied strain.

Original languageEnglish (US)
Article number141305
JournalMaterials Science and Engineering A
Volume815
DOIs
StatePublished - May 20 2021

Keywords

  • Ductility
  • Duplex microstructure
  • In situ neutron diffraction
  • Magnesium-lithium alloy

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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