Origin of the strain glass transition in Ti50(Ni50−x Dx) alloys

•The strain glass transition phenomenon in TiNi-based alloys is rationalized.•The electronic-structure origins of the strain glass transition are uncovered.•The separation of domains with different compositions is explained.

Direct evidence was recently discovered for the unique strain glass (STG) transition, which breaks the local symmetries (PRL 112, 025701 (2014)). To understand the origin of the STG transition, the effects of doping point defects on Ti50(Ni50−x Dx) are investigated using first-principle calculations. The experimental observation that STG only exists in a limited range of chemical composition x is successfully rationalized. The mechanisms that correspond to the division of a system into domains with distinctly different compositions are found to be directly related to a dip in the defect formation energy.