Elastic and superelastic properties of Co49Ni22Ga29 single crystal

Low-frequency-elastic modulus, internal friction, tensile stress-strain loops, and thermally induced strain recovery are studied in the vicinity of the martensitic transformation (MT) exhibited by the [001]-oriented Co49Ni22Ga29 single crystal in as-grown state. The mechanical and thermomechanical tests are conducted with TA Instruments Q800 dynamic mechanical analyzer. Elastic modulus shows softening during cooling and a deep minimum at MT concurrently with the abrupt increase of internal friction. The stepwise and jerky yield and recovery of the superelastic 7% strain alongside the appearance of the jumplike character of thermally induced MT are obtained after thermomechanical training. Thermodynamic estimations reveal a self-consistency of the results.