Elastocaloric Effect Associated with Different Types of Martensitic Transformations: Typical First‐Order and Weak First‐Order Ones. Issue 2 (25th August 2017)

• Record Type: Journal Article
• Authors: Xiao, Fei; Fukuda, Takashi; Jin, Xuejun; Liu, Jian; Kakeshita, Tomoyuki
• Other Names: Entel Peter guestEditor.; Fähler Sebastian guestEditor.
• Is Part Of: Physica status solidi. Volume 255:Issue 2(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-08-25
• Subjects: elastic strain -- Heusler alloys -- iron–palladium alloys -- lattice softening -- martensitic transformation -- superelasticity; Solid state physics -- Periodicals; Solids -- Periodicals; Atomic structure -- Periodicals; 530.41
• DOI: 10.1002/pssb.201700246
• Languages: English
• ISSNs: 0370-1972

Abstract

Abstract : Elastocaloric effects of a Ni50 Fe19 Ga27 Co4 alloy exhibiting a typical first‐order martensitic transformation (MT) and an Fe‐31.2Pd (at.%) alloy exhibiting a weak first‐order MT, respectively, have been compared using their single crystals. A flat region appears in the temperature dependence of elastocaloric effect in the Ni50 Fe19 Ga27 Co4 alloy, while such region is missing in the Fe‐31.2Pd alloy. The elastocaloric effect of the Ni50 Fe19 Ga27 Co4 alloy originates essentially from the latent heat released by the stress‐induced MT, while that in the Fe‐31.2Pd alloy originates essentially from the entropy change caused by elastic deformation of the parent and martensite phases. Although the Young's modulus in the [001] direction at M s is nearly the same for the two alloys ( E ∼ 2 GPa), its slope d E/ d T is largely different between the two alloys. It is approximately 0.003 GPa K −1 for the Ni50 Fe19 Ga27 Co4 alloy and 0.2 GPa K −1 for Fe‐31.2Pd alloy. Abstract : The adiabatic temperature decrease is caused by the removal of different compressive stresses for the Ni50 Fe19 Ga27 Co4 and Fe‐31.2Pd alloys which exhibit typical and weak first‐order martensitic transformations (MTs), respectively. The elastocaloric effect in the Ni50 Fe19 Ga27 Co4 and Fe‐31.2Pd alloys mainly comes from the entropy change during the stress‐induced MTs and the elastic deformation, respectively.