Thermal cycling response of Ni_45,3Ti_29,7Hf₂₀Pd₅ shape memory alloys

The shape memory properties and microstructure of the as-received and aged polycrystalline Ni_45,3Ti_29,7Hf₂₀Pd₅ shape memory alloys were investigated. It was revealed that their functional properties such as transformation temperatures, thermal hysteresis, dissipation energies strongly depend on thermal cycling, aging treatments and martensite morphology. Transformation temperatures decreased substantially with thermal cycling while thermal hysteresis and dissipation energies were closely linked to precipitate characteristics and only weakly affected by cycling.