| Summary: | The outstanding role of internal stress in the silicone matrix driving a magnetostrain reversal of embedded particles of the Ni–Mn-Ga ferromagnetic shape memory alloy after removal of magnetic field, has been disclosed by finite element (FE) simulations and validated by experiment. For simulations, the three case studies have been considered: an isolated particle, and the particles pairs aligned parallel or perpendicularly to the applied magnetic field. The isolated particle provided a 0.4 MPa of the reverse stress accumulated in a matrix that was insufficient to recover the composite shape after the removal of magnetic field. Simulations revealed that the strong elastic inter-particle interactions are needed to enhance both the local effective stiffness of composite and the reverse stress. The case where the particles pairs with the optimized inter-particle distance are aligned perpendicularly to the applied magnetic field, is more favorable to obtain the largest magnetostrain recovery. Simulation results demonstrate a 1.8% of the compressive magnetostrain of the 30 vol%Ni–Mn-Ga/silicone composite under the field applied parallel to the particles chains, which is in agreement with the experiment. The criteria for a selection of matrix, facilitating a large reversible magnetostrain of composite, have been determined.
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