Simultaneous XRD and Electrical Resistivity Measurements of the phase transitions in Co-Ni-Ga ferromagnetic shape memory alloy system

The experiments have been performed on bulk Co2NiGa samples in three states: quenched, deformed and quenched, and quenched and stabilized at 350ºC. The in situ X ray scans were performed along with ER measurements in the temperature range where the phase transformations occur. The tests have been done in the beryllium dome, with the electric resistance vs temperature (ER) measurements performed using a Keythley 2010 multimeter. The heating and cooling was performed between - 100 and + 200oC. The shape memory alloys were insulated using kapton foil from the heating device. The beam size used for the experiments and focused on the sample had to be limited due the contacts for the ER measurement device. Thus, corroborated with larger grain sizes for the investigated alloys, it is possible that only particular crystallographic orientations have been observed.