Initiation of basal slip and tensile twinning in magnesium alloys during nanoindentation

0491356 - ÚFM 2019 RIV CH eng J - Journal Article
Guo, T. - Šiška, Filip - Cheng, J. - Barnett, M.
Initiation of basal slip and tensile twinning in magnesium alloys during nanoindentation.
Journal of Alloys and Compounds. Roč. 731, JAN (2018), s. 620-630. ISSN 0925-8388. E-ISSN 1873-4669
Institutional support: RVO:68081723
Keywords : pop-in * single-crystals * deformation mechanisms * spherical indentation * incipient plasticity * neutron-diffraction * dislocation density * mg alloys * az31 * dependence * Nanoindentation * Basal slip * Twin * Magnesium * Solute strengthening
OECD category: Materials engineering
Impact factor: 4.175, year: 2018

The present study addresses the challenge of determining the stress required for the initiation of deformation modes in Mg alloys. Nanoindentation is employed to detect the onset of basal slip and tensile twinning. A Mg-6 wt. % Zn alloy and a series of Mg-Gd binary alloys with concentrations between 0.3 and 4 wt. % Gd are examined in the extruded state. Nanoindentation tests were conducted on {10 (1) over bar0} and {11 (2) over bar0} crystal planes using a 5 mu m radius spherical indenter. It is shown that the initial yielding point in the load trace corresponds to the appearance of basal slip lines on the sample surface. A pop-in event is seen to accompany the appearance of twinning. We find that the addition of Zn strengthens the basal slip but shows mild influence on twin initiation. For alloying with Gd, an impact on basal slip and twinning is only seen at the highest solute levels. A means of examining the alloying effect on twin growth is proposed and revealed that solute Zn has a greater impact on twin growth than initiation. Crown Copyright (C) 2017 Published by Elsevier B.V. All rights reserved.
Permanent Link: http://hdl.handle.net/11104/0289757