Premium
The Role of Adaptive Martensite in Magnetic Shape Memory Alloys
Author(s) -
Niemann Robert,
Rößler Ulrich K.,
Gruner Markus E.,
Heczko Oleg,
Schultz Ludwig,
Fähler Sebastian
Publication year - 2012
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201200058
Subject(s) - martensite , materials science , magnetic refrigeration , microstructure , shape memory alloy , condensed matter physics , hysteresis , crystal twinning , magnetic shape memory alloy , actuator , phase (matter) , phase boundary , metallurgy , magnetic field , magnetic domain , magnetization , computer science , physics , quantum mechanics , artificial intelligence
Magnetic shape memory materials require a high twin boundary mobility and low hysteresis for applications mainly as actuators, sensors, and magnetocaloric cooling elements. Usually, outstanding properties are found only in samples with a modulated martensitic structure. Here, we analyze the question why a modulated structure is beneficial and show evidence that the modulated martensite is not an equilibrium phase but a nanoscale microstructure of non‐modulated (NM) martensite. In this review, we combine results from continuum and atomistic theory, as well as local and integral measurements on the model system Ni–Mn–Ga. Following the concept of adaptive martensite the modulated phase forms to minimize elastic energy near the phase boundary by introducing low‐energy twin boundaries between lamellae of the NM martensite that have widths of a few unit cells.