Effects of Yttrium Addition on Bending Deformation Behavior of Magnesium Single Crystals

Abstract

Pure magnesium and Mg–Y alloy single crystals were subjected to three-point bending tests to investigate the effect of crystal orientation and yttrium on bending deformation behavior. Specimens whose neutral planes are parallel to (0001) and neutral axes are [1120] deformed due to basal slips, displaying a gull-shape. Their bending yield stresses increased by addition of yttrium and were controlled by the shear stress on the basal plane. Conversely, neutral planes parallel to (1100) and neutral axes are [1120] resulting in specimens deformed due to {1012} twins occurred at the compression side, basal slips within the twins and finally showed a V-shape. In Mg–Y alloys, first order pyramidal ⟨c + a⟩ slips (FPCS) and {1011}-{1012} double twins were also activated in the tension area. Their bending yield stresses and bending ductility increased by yttrium addition. Strain induced by {1011}-{1012} double twins at the tension side was very low. FPCS was found to be activated by addition of yttrium and to increase bending ductility.

 

This Paper was Originally Published in Japanese in J. Japan Inst. Met. Mater. 84 (2020) 344–351.

Fig. 13 Optical micrographs of (a) 0.15Y-E1 after yielding, (b) basal slips within {10-12} twins in compression area and (c) slip lines caused by FPCS and twins in tension area.