Shape Memory and Superelastic Ceramics at Small Scales

TitleShape Memory and Superelastic Ceramics at Small Scales
Publication TypeJournal Article
Year of Publication2013
AuthorsLai, A, Du, Z, Gan, CLip, Schuh, CA
JournalScience
Volume341
Issue6153
Pagination1505 - 1508
Date Published2013/09/27/
Abstract

Shape memory materials are a class of smart materials able to convert heat into mechanical strain (or strain into heat) by virtue of a martensitic phase transformation. Some brittle materials such as intermetallics and ceramics exhibit a martensitic transformation but fail by cracking at low strains and after only a few applied strain cycles. Here we show that such failure can be suppressed in normally brittle martensitic ceramics by providing a fine-scale structure with few crystal grains. Such oligocrystalline structures reduce internal mismatch stresses during the martensitic transformation and lead to robust shape memory ceramics that are capable of many superelastic cycles up to large strains; here we describe samples cycled as many as