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 beta-Ti alloys are demonstrated. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim