Strain glass and ferroic glass - Unusual properties from glassy nano-domains

The present article serves as a concise review of strain glass and its broader concept - ferroic glass. Strain glass is a frozen disordered strain state composed of nano-sized strain domains, which is formed due to the frustration created by point defects or dopants. Such frustration creates glassy nano-sized martensite-like domains that do not grow into a macroscopic martensite during cooling and instead show typical glass-freezing dynamics. Strain glass bears much resemblance with the glass phenomena found in other two types of ferroic systems, relaxor ferroelectric, and spin glass. These three ferroics-based glasses are thus called ferroic glasses. Characteristics of strain glass, including recent in situ high-resolution TEM images, are shown. Unusual properties associated with strain glass, such as superelasticity with narrow hysteresis, high-damping, and low modulus, as well as Invar and Elinvar effect in cold-rolled β-Ti alloys are demonstrated. Strain glass is a frozen disordered strain state composed of nano-sized strain domains, which is formed due to the frustration created by point defects or dopants. It bears much resemblance with the glass phenomena found in other two types of ferroic systems: relaxor ferroelectric and cluster spin glass. Unusual properties associated with strain glass, such as superelasticity with narrow hysteresis, high damping and low modulus, as well as Invar and Elinvar effect in cold-rolled β-Ti alloys are demonstrated.