Effects of demagnetization on Magnetic-Field-Induced Strain and microstructural evolution in Ni-Mn-Ga Ferromagnetic Shape Memory Alloy by phase-field simulations. (5th October 2016)

• Record Type: Journal Article
• Authors: Peng, Qi; Huang, Junjie; Chen, Mingxiang
• Is Part Of: Materials & design. Volume 107(2016)
• Page Start: 361
• Page End: 370
• Publication Date: 2016-10-05
• Subjects: Ferromagnetic Shape Memory Alloy -- Magnetic-Field-Induced Strain -- Ni-Mn-Ga -- Phase-field simulation -- Demagnetization effect -- Martensite reorientation; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2016.06.050
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: Demagnetization effect plays a vital role in ferromagnetic materials. However, its influence on Magnetic-Field-Induced Strain (MFIS) in Ni-Mn-Ga Ferromagnetic Shape Memory Alloy has not yet been fully quantified. This study investigates demagnetization effects on MFIS and microstructural evolution in Ni-Mn-Ga for different demagnetization factors (i.e. vector N ) by phase-field simulations. The investigation reveals that demagnetization can exert substantial impact on both macroscopic and microscopic behavior of Ni-Mn-Ga through the influence of internal magnetic field on twin boundary movement and domain evolution. The switching field and the saturating field as well as their difference increase with N f (component of N parallel to easy axis of field-favored martensitic variant). For larger N f values, the increase of strain appears to be less sharp and more stable (hardening-like). The stable increase of strain is ascribed to the steady movement of twin boundary. The velocity of magnetic domain wall motion during MFIS process decreases as N u (component of N parallel to easy axis of field-unfavored martensitic variant) increases and their relationship obeys the power law. However, N u does not seem to affect strain behavior or twin boundary movement. The dependence of switching field and saturating field on N f is established for application design purposes. Graphical abstract: Highlights: Demagnetization effects on field-induced strain and microstructure in Ni-Mn-Ga are investigated by phase-field simulations. Demagnetization significantly affects both macro-behavior and microstructural evolution in Ni-Mn-Ga under an applied field. Demagnetization factor parallel to field-favored variant's easy axis affects critical field, strain, twin boundary motion. Demagnetization factor parallel to field-unfavored variant's easy axis affects domain wall motion during strain increase. Demagnetization affects behavior of Ni-Mn-Ga by influence of internal magnetic field on twin boundary and magnetic domain.