Electron beam welding of Fe–Mn–Al–Ni shape memory alloy: Microstructure evolution and shape memory response

The present study reports on the impact of abnormal grain growth (AGG) on the microstructural evolution following electron beam (EB) welding of Fe–Mn–Al–Ni shape memory alloy (SMA). Polycrystalline sheet-like material was EB-welded and a cyclic heat treatment, studied in previous work, was conducted for inducing AGG and a bamboo-like microstructure, respectively. Optical and electron microscopy were carried out to characterize the prevailing microstructure upon cyclic heat treatment. For characterization of the functional properties following AGG, a load increase test was conducted. The current results clearly show that good shape memory response can be obtained in Fe–Mn–Al–Ni SMA upon EB welding and subsequent post-heat treatment. These results further substantiate the potential use of conventional processing routes for Fe–Mn–Al–Ni SMA.