First-principles and experimental study on interfacial fracture in Mg alloys

Tsuru, Tomohito   ; Somekawa, Hidetoshi*

Mg alloys are promising candidates for next generation of structural lightweight materials in practical use, especially for transportation equipment in terms of energy and environmental conservation. Based on the assumption of brittle fracture of Mg alloys, the interfacial separation caused by segregated solutes in Mg can be described efficiently by the energy-based criterion of fracture, which is good agreement with the fracture toughness of experimental test for Mg-M binary alloys. The electronic interaction, that is the change in electronic states between interface and surface, dominantly influences the ideal work of separation regardless of the type of interface. We found that d1 and d2 solutes such as Zr have a distinctive hybridization between p-band of Mg and d-band of solutes, which characterizes a strong fracture toughness of Zr-doped Mg alloys in both calculations and experiments.