Ferrous Polycrystalline Shape-Memory Alloy Showing Huge Superelasticity

• Published in: Science (American Association for the Advancement of Science) Vol. 327; no. 5972; pp. 1488 - 1490
• Main Authors: Tanaka, Y, Himuro, Y, Kainuma, R, Sutou, Y, Omori, T, Ishida, K
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 19.03.2010; The American Association for the Advancement of Science
• Subjects: Alloys; Applied sciences; Betting; Crystallography; Ductility; Elasticity. Plasticity; Exact sciences and technology; Grain boundaries; Magnetization; Martensite; Martensitic transformation; Materials; Materials science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Mechanics; Metals. Metallurgy; Room temperature; Tensile stress; Nickel base alloys; Superplasticity; Magnetization; Shape memory alloy; Mechanical properties; Copper base alloys; Tensile strength
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1183169

Shape-memory alloys, such as Ni-Ti and Cu-Zn-Al, show a large reversible strain of more than several percent due to superelasticity. In particular, the Ni-Ti-based alloy, which exhibits some ductility and excellent superelastic strain, is the only superelastic material available for practical applications at present. We herein describe a ferrous polycrystalline, high-strength, shape-memory alloy exhibiting a superelastic strain of more than 13%, with a tensile strength above 1 gigapascal, which is almost twice the maximum superelastic strain obtained in the Ni-Ti alloys. Furthermore, this ferrous alloy has a very large damping capacity and exhibits a large reversible change in magnetization during loading and unloading. This ferrous shape-memory alloy has great potential as a high-damping and sensor material.