Microstructure and phase transformation of Ni46Mn33Ga17Cu4−xZrx alloys

• Alloy changed from single phase to dual phase after adding Zr.
• Formation of γ phase altered phase transformation temperature and enthalpy.
• Transformation temperature and enthalpy of dual phase alloys changed after aging.

This study investigated microstructure and phase transformation of Ni46Mn33Ga17Cu4−xZrx (x=0, 2, and 4) alloys. The substitution of Cu by Zr changed the alloy from a single martensite to a dual phase consisting of martensitic matrix and Zr-rich second γ phase at room temperature. The volume fraction of γ phase increased with the increase of Zr content, which resulted in the change of martensitic transformation temperature and transformation enthalpy of the alloys. After aging the dual phase alloys at 400 °C and 600 °C for 10 h, the martensitic transformation temperature was increased and transformation enthalpy was decreased.