Crack propagation behaviour in magnesium binary alloys

Abstract

The effect of alloying elements on crack propagation behaviour was investigated using extruded Mg–Ca and Mg–Zn binary alloys, with and without {} type deformation twins (DT). These alloys had similar microstructures grain boundary (GB) structure, basal texture, and grain size of ~30 μm. Most of the cracks in the Mg–Ca alloys were propagated along the high-angle GBs, i.e. exhibiting intergranular fracture, regardless of the existence of DT. On the other hand, crack propagation behaviour in the Mg–Zn alloy was influenced by the presence of twin boundaries (TBs). The fraction of TBs that was associated with the crack propagation showed higher in the twin-induced Mg–Zn alloy. These crack propagation tendencies resulted from modification of the TB energies by additional alloying elements.

Keywords:

• magnesium alloy
• grain boundary
• twin
• solute atom

Acknowledgements

The authors are grateful to Ms R. Komatsu (National Institute for Materials Science) for her technical help and to Profs Y. Shibutani and D. Matsunaka (Osaka University) for their constructive discussion.

Additional information

Funding

Funding. This work was partially supported by the JSPS Grant-in-Aid in [grant number 23760675] and [grant number 25420765].