Influence of Yttrium Addition on Plastic Deformation of Magnesium

Abstract

In this study, tensile tests of Mg-Y alloy single crystals and polycrystals were carried out to investigate influence of yttrium on activities of <c＋a> slip systems and a relationship between ductility of magnesium and active <c＋a> slip systems. Tensile directions of the single crystals and the polycrystals were parallel to （0001） and its rolling direction, respectively. Both tests were carried out at room temperature. Yield stress and ductility of Mg-（0.6-1.1） at％Y alloy single crystals were higher than that of pure Mg and the crystals were yielded due to first order pyramidal <c＋a> slip （FPCS） . Mg-0.9 at％Y alloy polycrystals showed higher ductility than pure Mg. The number of grains in which second order pyramidal slip can be activated was larger than that of non-basal slips in pure Mg, while the number for FPCS was increased with increasing strain in Mg-0.9 at％Y alloy. We supposed that high ductility of Mg-0.9 at％Y alloy would be caused activation of FPCS by yttrium addition. ［doi:10.2320/jinstmet.J2017016］

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

“…19 indicate activation stress of FPCS in [11 20] calculated from CRSSs for FPCS of pure Mg 13) and Mg0.6 at%Y (0.6Y). 14) Activation stress of FPCS was found to be independent of yttrium addition, as shown in Fig. 19.…”

“…Bending strain, ε (%) Bending strain, ε (%) Pure Mg [13] 0.6Y [14] Activation stress of FPCS Cracking point…”

“…Pure Mg [13] 0.6Y [14] Bending stress, , / MPa Bending stress, , / MPa Fig. 19 Bending stress bending strain curves of (a) Mg-E3 and (b) 0.25Y-E1.…”

Tensile Deformation Behavior of Magnesium Single Crystals with Different Yttrium Concentrations

“…Ando et al [4] have reported that pure magnesium single crystals deformed due to activation of second order pyramidal <c+a> slip in [112 � 0] tensile tests. On the other hand, Rikihisa et al [5] have reported that Mg-(0.6-1.1)at.%Y alloys deformed due to activation of first order pyramidal <c+a> slip in [112 � 0] tensile tests and showed high ductility at room temperature. However, the reason behind the change and activation of these slip systems have not been yet elucidated.…”