Experimentally quantifying critical stresses associated with basal slip and twinning in magnesium using micropillars

Y. Liu, N. Li, M. Arul Kumar, S. Pathak, J. Wang, R. J. McCabe, N. A. Mara, C. N. Tomé

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82 Scopus citations


Basal slip and {011¯2} twinning are two major plastic deformation mechanisms in hexagonal closed-packed magnesium. Here we quantify the critical stresses associated with basal slip and twinning in single-crystal and bi-crystal magnesium samples by performing in situ compression of micropillars with different diameters in a scanning electron microscope. The micropillars are designed to favor either slip or twinning under uniaxial compression. Compression tests imply a negligible size effect related to basal slip and twinning as pillar diameter is greater than 10 μm. The critical resolved shear stresses are deduced to be 29 MPa for twinning and 6 MPa for basal slip from a series of micropillar compression tests. Employing full-field elasto-visco-plastic simulations, we further interpret the experimental observations in terms of the local stress distribution associated with multiple twinning, twin nucleation, and twin growth. Our simulation results suggest that the twinning features being studied should not be close to the top surface of the micropillar because of local stress perturbations induced by the hard indenter.

Original languageEnglish (US)
Pages (from-to)411-421
Number of pages11
JournalActa Materialia
StatePublished - Aug 15 2017

Bibliographical note

Funding Information:
Y.L, M.A.K, R.J.M, C.N.T acknowledge support by the Office of Basic Energy Sciences, Project FWP 06SCPE401, under US DOE Contract No W-7405-ENG-36. J.W acknowledges support by the US National Science Foundation (NSF-CMMI) under grant No.1661686. The authors acknowledge the single-crystal magnesium preparation done by Prof. Y. Jiang and Dr. Q. Yu at University of Nevada, Reno, under Contract FEIN #886000024, and Dr. R.A. Lebensohn (MST-8, Los Alamos National Laboratory) for making available the EVPFFT code used for the numerical simulations. This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. Los Alamos National Laboratory, an affirmative action equal opportunity employer, is operated by Los Alamos National Security, LLC, for the National Nuclear Security Administration of the U.S. Department of Energy under contract DE-AC52-06NA25396. The research was performed in part in the Nebraska Nanoscale Facility: National Nanotechnology Coordinated Infrastructure and the Nebraska Center for Materials and Nanoscience, which are supported by the National Science Foundation under Award ECCS: 1542182, and the Nebraska Research Initiative. Access to microscopy facilities at the Electron Microscopy Lab at Los Alamos National Laboratories is also acknowledged.

Publisher Copyright:
© 2017


  • Basal slip
  • Magnesium
  • Micropillar compression
  • Twin


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