Effect of grain size on the superelastic response of a FeMnAlNi polycrystalline shape memory alloy

The effect of heat treatments on superelasticity was investigated in a FeMnAlNi polycrystalline alloy using incremental tensile strain tests at room temperature. Large grains of more than several millimeters can be obtained by a cyclic heat treatment process and the average grain size can be controlled by the number of heat treatment cycles. Improved superelastic response is observed in samples with large relative grain sizes, exhibiting increased elongation to fracture, lower critical stress for transformation, and higher reversibility. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.