Stress corrosion cracking of Ni2MnGa magnetic shape memory alloy in water and moist atmosphere

We prepared two kinds of cracks (surface cracks and transfixion cracks) to in situ study stress corrosion cracking of seven-layered (which is denoted as 7 M or 14 M) off-stoichiometric Ni2MnGa magnetic shape memory alloy in deionized water and moist atmosphere under constant deflection at room temperature. The experimental results showed that the cracks could nucleate and propagate continuously or discontinuously for a distance after some incubation time, and then arrest in water or moist atmosphere under constant deflection. The delayed cracking of Ni2MnGa alloy is regarded as reduction of the surface energy induced by adsorption of water molecule.