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This content will become publicly available on September 17, 2019

Title: In-situ neutron diffraction of a quasicrystal-containing Mg alloy interpreted using a new polycrystal plasticity model of hardening due to {10.2} tensile twinning

Due to the excellent balance of strength and ductility exhibited by some Mg-Zn-RE (Y subgroup rare earth element) alloys, which contain icosahedral quasicrystalline precipitates, it is of interest to examine their deformation mechanisms. Furthermore, the internal strain evolution Mg-3at%Zn-0.5 at%Y with 4 vol% i-phase was measured using in-situ neutron diffraction. The extruded samples exhibit an initially weak <10.0> || extrusion direction “rod texture,” distinct from the normally strong texture of extruded Mg alloys, but the grain size is unexceptional (16.7 ± 2.1 μm). The initially weak texture contributes to a nearly symmetric yielding response between tension and compression. The hardening responses are asymmetric, however, since {10.2} extension twinning is significantly more active during compressive straining, despite the initially weak texture. In-situ neutron diffraction tension and compression experiments parallel to the extrusion direction, together with elasto-plastic self-consistent (EPSC) crystal plasticity modeling, reveal the strength and hardening behavior of individual slip and twinning modes. A model that was previously published about twinning-detwinning (TDT) is implemented within the EPSC framework, and it is proven effective for describing the observed, mild tension-compression asymmetry. This is not possible with previous EPSC-based models of twinning. Finally, the description of hardening within the TDT model is modified,more » in order to accurately describe the evolution of internal strains within the twins.« less
 [1] ; ORCiD logo [2] ;  [1] ;  [1] ;  [1] ;  [2] ;  [3] ; ORCiD logo [4] ;  [5]
  1. Univ. of Virginia, Charlottesville, VA (United States). Materials Science and Engineering
  2. National Inst. of Materials Science, Tsukuba (Japan)
  3. Kobe Univ. (Japan). Mechanical Engineering
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  5. McMaster Univ., Hamilton, ON (Canada). Mechanical Engineering
Publication Date:
Report Number(s):
Journal ID: ISSN 0749-6419
Grant/Contract Number:
Accepted Manuscript
Journal Name:
International Journal of Plasticity
Additional Journal Information:
Journal Volume: 100; Journal Issue: C; Journal ID: ISSN 0749-6419
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
36 MATERIALS SCIENCE; precipitation; quasicrystal; icosahedral; twinning; neutron diffraction; internal stress
OSTI Identifier: