ADVANCED MATERIALS & PROCESSES | OCTOBER 2023 44 SMJ HIGHLIGHTS June 2023 CALORIC EFFECTS INDUCED BY UNIFORM AND NON-UNIFORM STRESS IN SHAPE-MEMORY MATERIALS Marcel Porta, Teresa Castán, Avadh Saxena, and Antoni Planes A Ginzburg–Landau model is developed that is adequate to describe a square-to-rectangle martensitic transition with associated shape-memory and superelastic properties. Using this model, the authors study caloric effects in the vicinity of the martensitic transition induced by stress, and compare the case of a uniform uniaxial stress and the case of a non-uniform continuous distribution of stresses that produce bending of the material. The former case corresponds to an elastocaloric effect, and the latter corresponds to a flexocaloric effect. The aim of the work is to quantitatively compare both cases, which the authors show must be accomplished in terms of equal amounts of exchanged mechanical work. It is then obtained that the flexocaloric effect is more efficient for low exchanged work but less efficient for large, exchanged work (Fig. 2). 12 Fig. 2 — (a) Deviatoric strain pattern of a bent beam at T0 = 1.05Tc, above the transition temperature in the absence of stress, T0 = 1.29Tc. Light (dark) regions represent positive (negative) strain. The strain generated microstructure is enlarged, showing the nucleation of the two different variants of the rectangular phase at opposite sides of the beam, while the central part remains untransformed. (b) Characteristic zig-zag strain microstructure of the rectangular phase obtained at T = 0.8Tc, well below the transition temperature. (c) Microstructural changes associated with bending observed experimentally in Cu–Al–Ni. (a) (b) (c) SMJ CALL FOR PAPERS Shape Memory and Superelasticity: Advances in Science and Technology, the official journal of the International Organization on Shape Memory and Superelastic Technologies (SMST), an affiliate of ASM International, is actively seeking manuscripts. Shape Memory and Superelasticity: Advances in Science and Technology publishes original peer-reviewed papers that focus on shape memory materials research, with contributions from materials science, experimental and theoretical mechanics, and physics with cognizance of the chemistry, underlying phases, and crystallography. Topics where new papers are welcome include: • All classes of shape memory materials including metals, non-metals, polymers, and ceramics • Stress-strain response in thermo-mechanical loadings • Life prediction methodologies • Thermodynamics of transformation • Solutions to shape memory problems in industry • Critical experiments that shed insight into shape memory behavior • Novel experimental techniques for shape memory response • Single crystals and polycrystals of shape memory metals • Shape memory response under coupled mechanical- mechanic fields, magnetic shape memory, and thermo- caloric effects Instructions for authors and submission information can be found here: https://www.springer.com/journal/40830.
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