| Local Deformation Behavior of Mg Alloy Single Crystals using Ball Indenter Hiromoto Kitahara1; Momoka Watanabe1; Shinji Ando1; 1KUMAMOTO UNIVERSITY, Kumamoto, Japan; PAPER: 295/Magnesium/Regular (Oral) SCHEDULED: 16:45/Fri. 25 Oct. 2019/Adonis ABSTRACT: A steel ball indenter was impressed on low index planes in Mg alloy single crystals with different CRSSs: Mg-Al, Mg-Zn, and Mg-Y alloy single crystals. Effects of alloying elements on indentation behavior and roles of slip and twins on indentation size were investigated. Pure Zn single crystals, whose loading direction causing {10-12} twins is opposite to pure Mg, were also prepared. Indentations showed a circular shape on (0001) in the Mg alloys and pure Zn single crystals. Also, slip lines and twins were hardly observed around (0001) indentations. On the other hand, (10-10) and (1-210) indentations showed an elliptical morphology which elongated to [0001]. Basal slip lines and {10-12} twins were observed around (0001) indentations in Mg-Al and Mg-Zn alloys. Twins, however, were hardly observed in Mg-Y alloy single crystals. Indentation sizes of (0001) of the Mg alloys were smaller than that of pure Mg. Also, indentation sizes of pure Mg and Zn were nearly the same. Indentation sizes decreased with increasing CRSS for the basal slip. Therefore, the size would be determined by CRSS for the basal slip. CRSSs for the basal slip of pure Mg and Zn were nearly the same. Therefore, the size gap would be caused by the presence of {10-12} twins. In Mg alloys, indentation sizes decreased as alloy elements were added. The size differences between pure Mg and the Mg alloys would be determined by ratios of basal slip and twinning activities. |
