Two way shape memory effect in CuZnAl single crystals after pseudoelastic cycling at low temperatures

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 517; no. 1; pp. 118 - 124
• Main Authors: Malarría, J., Lovey, F.C., Sade, M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 20.08.2009; Elsevier
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; CuZnAl; Dislocations; Elasticity, elastic constants; Exact sciences and technology; Martensitic transformations; Materials science; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Pseudoelasticity; Single crystals; Two way shape memory effect; Single crystals; Pseudoelasticity; Two way shape memory effect; CuZnAl; Dislocations; Martensitic transformations; Thermal cycle; Precipitates; Heat treatments; Shape memory effects; Zinc alloys; Retained austenite; Monocrystals; Aluminium alloys; Superelasticity; Copper alloys; Dislocation arrays; Microstructure; Defect formation; Transition element alloys
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2009.03.044

CuZnAl alloys show pseudoelasticity, shape memory behavior and if adequately treated also the two way shape memory effect (TWSME), i.e., shape change due to the martensitic transition both during cooling and by heating. The origin of this phenomenon has been strongly discussed and the role that diffusion and dislocations play on the introduction of the TWSME has been and still is discussed in the literature. However many of the reported training or educational methods show the overlapping of dislocation generation and diffusion both in the austenite and in the martensite. This work deals with the introduction of the TWSME in CuZnAl single crystals by pseudoelastic cycling at temperatures low enough to disregard the contribution of diffusion, which influences the martensitic bcc-M18R transition at temperatures as low as room temperature in these alloys. The microstructure responsible for the introduction of the TWSME is discussed and the analysis of the effect of dislocation arrays, retained martensite, precipitates and microplasticity is presented.