Strain glass and its novel properties

Strain glass is a frozen state of short-range-ordered lattice strains (nano-sized strain domains), which is found in shape memory alloy systems. Its physical properties show typical glassy features such as dynamic freezing and non-ergodicity. Microscopically, it is characterized by many randomly distributed nano-sized strain domains embedded in parent matrix. However, its average structure does not change with temperature. The strain glass system exhibits some unique transforming behaviors such as isothermal transition from strain glass to martensite and stress induced transition from strain glass to martensite. Moreover, strain glass exhibits multi-functional properties including shape memory effect, superelasticity, elastocaloric effect, damping effect, stress controlled damping together with Invar and Elinvar effects, which demonstrates such a new kind of metallic intelligent material has big potential in application. The multi-functional properties of strain glass are closely related with its microstructure, and they originate from the response of its nano-sized strain domains to the temperature and external field.