Modeling Rearrangement Process of Martensite Platelets in a Magnetic Shape Memory Alloy Ni2MnGa Single Crystal under Magnetic Field and (or) Stress Action

Abstract

The aim of the article is the modeling of the rearrangement process between martensite variants in order to use magnetic shape memory alloys (MSMs) as actuators. In the framework of the thermodynamics of irreversible processes, an efficient choice of the internal variables to take into account the magnetic and mechanical actions and a free energy function are stated. The behavior is chosen as magnetically reversible and mechanically irreversible. An equivalence between magnetic field action H and uniaxial stress action for the initiation of the rearrangement is established. Finally, model predictions are compared with experimental measurements.

Irreversible Thermodynamics and Smart Materials Systems Modelling. Example of Magnetic Shape Memory actuators

“…Good descriptions of internal variables used to model irreversible behaviour in MSMA smart materials are presented in Gauthier et al (2007) and Sarawate and Dapino (2010). Three internal variables are required to model a simplified two-variants microstructure of an MSMA sample: two internal variables α and θ are reversible (dependent variables) whereas the third internal variable ξ is related to the irreversible behavior (independent variable).…”

Magnetic Shape Memory Alloys as smart materials for micro-positioning devices

“…In [23,24,25], such models are proposed whereas in [26,27,28], a more mechatronics-based approach is taken. They explicitly take into account the salient features (dynamics of system) required to make actuators.…”

Ni-Mn-Ga single crystal Shape Memory Alloy magneto-thermomechanical modeling

“…But, in [1], the value of λ was considered depending on the previous strain history. The concept of memorized point was introduced and a difference appears between partial loops and major loops.…”

“…A model of rearrangement process of martensite platelets in a non-stoichiometric Ni 2 MnGa MSMA single crystal under magnetic field and (or) stress actions has been proposed by the same authors in [1]. The aim of this following paper is to extend these works purpose to the anisothermal behavior when including the process of martensite platelets reorientation and phase transformation austenite ⇋ martensite.…”