Thermo-magnetic characterization of phase transitions in a Ni-Mn-In metamagnetic shape memory alloy

JOURNAL OF ALLOYS AND COMPOUNDS

卷:887

Article

Romero, Francisco Javier¹  Martin-Olalla, Jose-Maria¹  Blazquez, Javier S.¹  Gallardo, Maria Carmen¹  Soto-Parra, Daniel²  Vives, Eduard³  Planes, Antoni³ 

[1] Univ Seville, Fac Fis, Dept Fis Mat Condensada, ICMSE CSIC, Avenida Reina Mercedes S-N, ES-41080 Seville, Spain

[2] Tecnol Nacl Mexico, Inst Tecnol Delicias, Paseo Tecnol Km 35 Cd, Delicias 33000, Chihuahua, Mexico

[3] Univ Barcelona, Fac Fis Marti & Franques 1, Dept Fis Mat Condensada, Barcelona 08028, Spain

关键词: Metals and alloys;    Heat capacity;    Entropy;    Kinetics;    Magnetization;   

DOI  :  10.1016/j.jallcom.2021.161395

来源: Elsevier

【 摘 要 】

The partially overlapped ferroelastic/martensitic and para-ferromagnetic phase transitions of a Ni50.53Mn33.65In15.82 metamagnetic shape memory alloy have been studied from calorimetric, magnetic and acoustic emission measurement. We have taken advantage of the existence of thermal hysteresis of the first order ferroelastic/martensitic phase transition (similar to 2.5 K) to discriminate the latent heat contribution Delta H-t = 7.21(15)kJkg(-1) and the specific heat contribution Delta H-c = 216(1)Jkg(-1) to the total excess enthalpy of the phase transition. The specific heat was found to follow a step-like behavior at this phase transition. The intermittent dynamics of the ferroelastic/martensitic transition has been characterized as a series of avalaches detected both from acoustic emission and calorimetric measurements. The energy distribution of these avalanche events was found to follow a power law with a characteristic energy exponent epsilon congruent to 2 which is in agreement with the expected value for a system undergoing a symmetry change from cubic to monoclinic. Finally, the critical behavior of the para-ferromagnetic austenite phase transition that takes place at similar to 311 K has been studied from the behavior of the specific heat. A critical exponent alpha congruent to 0.09 has been obtained, which has been shown to be in agreement with previous values reported for Ni-Mn-Ga alloys but different from the critical divergence reported for pure Ni. (C) 2021 The Author(s). Published by Elsevier B.V.

【 授权许可】

Free