The suppression and recovery of martensitic transformation in a Ni-Co-Mn-In magnetic shape memory alloy

The intrinsic mechanism of the martensitic transformation (MT) suppression observed in Ni-Co-Mn-In alloys fabricated under non-equilibrium conditions still remains mysterious. Here, we used the undercooling technique to obtain a solidified microstructure in non-equilibrium state, subsequently leading to MT suppression even further cooling to 10 K. It was found that primary dendrite-like In-depleted precipitates occurred during solidification under a large undercooling. After a prolonged annealing, the MT interestingly appeared again due to the dissolution of the precipitates and the recovery of equilibrium chemical composition in the matrix. (C) 2011 Elsevier B. V. All rights reserved.