Structural defects responsible for strain glassy transition in Ni$_{50+x}$Ti$_{50-x}$

TL;DR

This paper investigates the local structural defects in Ni$_{50+x}$Ti$_{50-x}$ alloys that inhibit long-range elastic strain order, leading to a strain glassy phase, by analyzing local atomic environments.

Contribution

It identifies the specific defect phase responsible for strain glass formation in Ni-Ti alloys through local structural analysis.

Findings

Defect phase inhibits long-range elastic order.

Local structure around Ni and Ti reveals defect role.

First identification of defect responsible for strain glass in this system.

Abstract

The strain glassy phase is produced by doping a small percentage of impurity in a martensitic alloy. Its ground state is conceived to consist of martensitic nano domains spatially separated from each other by a defect phase. The present study, by probing the local structure around the Ni and Ti in martensitic and strain glassy compositions of Ni$_{50+x}$Ti$_{50-x}$, for the first time, identifies the defect phase that is responsible for inhibiting the long range ordering of the elastic strain vector leading to the formation of the strain glassy phase.