Influence of Yttrium Addition on Plastic Deformation of Magnesium

In this study, tensile tests of Mg - Y alloy single crystals and polycrystals were carried out to investigate influence of yttrium on activities of slip systems and a relationship between ductility of magnesium and active 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 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 ductil - ity of Mg - 0 . 9 at ％ Y alloy would be caused activation of FPCS by yttrium addition. ［ doi:10 . 2320 / jinstmet.J2017016 ］