Journal of Materials Engineering and Performance, cilt.33, sa.9, ss.4640-4646, 2024 (SCI-Expanded)
Ultra-high strength of NiTiHfPd alloys have been promising for specific application areas of SMAs. Thus, the main objective of this study is to further understand the high strength behavior of the alloys through experimental and theoretical studies. Shape memory response of an ultra-high strength Ni45.3Ti29.7Hf20Pd5 alloy was systematically investigated after aging at 550 °C for 5 h via constant-stress temperature cycling and constant-temperature stress cycling experiments. Shape memory behavior under a wide range of compressive stress levels from 300 to 1200 MPa was reported before and after stress cycling of 5000 times. The alloys showed a reversible strain of 1.3% against an ultra-high stress of 2 GPa. It is concluded that the combination of high strength and temperature capability mainly stems from high chemical complexity in addition to aging and will be quite advantageous in practical applications.