Ductile fracture mechanism in fine-grained magnesium alloy

Abstract

Abstract The ductile fracture mechanism in a fine-grained magnesium alloy has been investigated by transmission electron microscopy-focused ion beam techniques. In coarse-grained or conventional magnesium alloys, twins form at the very beginning of the deformation process, and crack propagation occurs through the twin boundaries. However, in the alloy used in this study, subgrain structures were found instead of twins at the crack tip. Nanoscale twins formed subsequently owing to large stress in the crack propagation route. The fine-grained alloys showed high fracture toughness resulting from resistance to the twins at the beginning of the deformation. Keywords: magnesium alloysfracturedeformation twinningtwinsmicrostructureTEMFIB Acknowledgements The authors are grateful to Ms. M. Isaki (National Institute for Materials Science) for her technical help. This study was supported by JSPS Grant-in-Aid for Young Scientists (B) Grant No. 21760564.