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Critical resolved shear stresses for slip and twinning in Mg-Y-Ca alloys and their effect on the ductility
- Source :
- International Journal of Plasticity, 162, 103525, 2023
- Publication Year :
- 2023
-
Abstract
- The deformation mechanisms of an extruded Mg-5Y-0.08Ca (wt. %) alloy were analyzed by means of micropillar compression tests on single crystals along different orientations -- selected to activate specific deformation modes -- as well as slip trace analysis, transmission electron microscopy and transmission Kikuchi diffraction. The polycrystalline alloy presented a remarkable ductility in tension (~32%) and negligible differences in the yield strength between tension and compression. It was found that the presence of Y and Ca in solid solution led to a huge increase in the CRSS for <a> basal slip (29 $\pm$ 5 MPa), <c+a> pyramidal slip (203 $\pm$ 7 MPa) and tensile twin nucleation (above 148 MPa), while the CRSS for <a> prismatic slip only increases up to 105 $\pm$ 4 MPa. The changes in the CRSS for slip and tensile twinning in Mg-Y-Ca alloys expectedly modify the dominant deformation mechanisms in polycrystals. In particular, tensile twinning is replaced by <a> prismatic slip during compressive deformation along the a-axis. The reduction of twinning (which generally induces strong anisotropy in the plastic deformation in textured alloys), and the activation of <a> prismatic slip (which provides an additional plastic deformation mechanism with limited hardening) were responsible for the large tensile ductility of the alloy.
- Subjects :
- Condensed Matter - Materials Science
Subjects
Details
- Database :
- arXiv
- Journal :
- International Journal of Plasticity, 162, 103525, 2023
- Publication Type :
- Report
- Accession number :
- edsarx.2301.12154
- Document Type :
- Working Paper