Effect of composition on transformation temperatures of Ni–Mn–Ga shape memory alloys

The effect of the composition of Ni–Mn–Ga shape memory alloys (SMAs) on martensitic transformation temperature and enthalpy, Ms and ΔHc, respectively, can be analyzed by linear regression. Experimental results show that the effect of Mn content is relatively small, but Ni and Ga contents have a dramatic effect and their effects are opposed. The Ms temperature and ΔHc of stoichiometric Ni 2MnGa are predicted as 185 K and 1.2 J/g, respectively. The linear relationship between Ms and ΔHc indicates that Ni–Mn–Ga SMAs undergo thermoelastic martensitic transformation.