Giant two-way shape memory effect in high-temperature Ni–Mn–Ga single crystal

✍ Scribed by V.A. Chernenko; E. Villa; S. Besseghini; J.M. Barandiaran

• Publisher: Elsevier
• Year: 2010
• Tongue: English
• Weight: 387 KB
• Volume: 10
• Category: Article
• ISSN: 1875-3892
• DOI: 10.1016/j.phpro.2010.11.081

✦ Synopsis

A perfect two-way shape memory effect (TWSME) with reversible strain of about 9% has been found in the high-temperature Ni 57.5 Mn 22.5 Ga 20.0 single crystal transforming into 2M non-modulated martensitic phase. Two thermal/mechanical treatment routes were utilized in the experimental procedures. The outstanding high-temperature TWSME is observed as a result of tensile stress-strain cycling along <100> axis involving huge superelastic strains due to stress-induced martensitic transformation. It is argued that the TWSME is related to the anisotropic internal stresses produced by a network of lattice defects. The defects are generated in the course of oriented growth/shrinkage of the dominating martensitic variant in the tensile sample.