title: Reversible Martensitic Transformation under Low Magnetic Fields in Magnetic Shape Memory Alloys.
abstract: Magnetic field-induced, reversible martensitic transformations in NiCoMnIn meta-magnetic shape memory alloys were studied under constant and varying mechanical loads to understand the role of coupled magneto-mechanical loading on the transformation characteristics and the magnetic field levels required for reversible phase transformations. The samples with two distinct microstructures were tested along the [001] austenite crystallographic direction using a custom designed magneto-thermo-mechanical characterization device while carefully controlling their thermodynamic states through isothermal constant stress and stress-varying magnetic field ramping. Measurements revealed that these meta-magnetic shape memory alloys were capable of generating entropy changes of 14 J kg-1K-1or 22 J kg-1K-1, and corresponding magnetocaloric cooling with reversible shape changes as high as 5.6% under only 1.3 T, or 3 T applied magnetic fields, respectively. Thus, we demonstrate that this alloy is suitable as an active component in near room temperature devices, such as magnetocaloric regenerators, and that the field levels generated by permanent magnets can be sufficient to completely transform the alloy between its martensitic and austenitic states if the loading sequence developed, herein, is employed.
authors.affiliation: Department of Materials Science and Engineering, Texas A&M University, College Station, TX, USA.|Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA.
authors.forename: N M
authors.initials: NM
authors.lastname: Bruno
authors.affiliation: Department of Materials Science and Engineering, Texas A&M University, College Station, TX, USA.
authors.forename: S
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Materials Science and Engineering, Texas A&M University, College Station, TX, USA.|Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA.
authors.forename: I
authors.initials: I
authors.lastname: Karaman
authors.affiliation: Siberian Physical Technical Institute, Tomsk State University, Tomsk 634050, Russia.
authors.forename: Y I
authors.initials: YI
authors.lastname: Chumlyakov