Shape memory characteristics of Ti49.5Ni25Pd25Sc0.5 high-temperature shape memory alloy after severe plastic deformation

Influence of tantalum additions on the microstructure and shape memory response of Ti 50.5 Ni 24.5 Pd 25 high-temperature shape memory alloy

“…It is capable of increasing the transformation temperatures of TiNi up to 500 1C while maintaining most of its attractive features such as reasonable ductility and work output, and significant strain recovery under stress-free and constrained conditions [2,5]. Since most of the potential high temperature actuation applications in oil and gas, aerospace, and automotive industries require intermediate working temperatures around 150-200 1C, TiNiPd compositions with 25-30 at% Pd would satisfy the need for solid-state actuation at these temperatures [6][7][8][9][10].…”

“…The problem is exacerbated for HTSMAs, since the materials, by definition, operate at elevated temperatures resulting in decreased strength levels and the possibility of thermally activated deformation processes [6,7,13]. Several solutions have been proposed to alleviate the dimensional instability problem in HTSMAs, all of which target improving the strength of the alloy through (a) solidsolution strengthening [8,14,15], (b) thermomechanical processing [9,16,17], and (c) precipitation hardening [18][19][20][21].…”

Effect of Thermal Treatments on Ni–Mn–Ga and Ni-Rich Ni–Ti–Hf/Zr High-Temperature Shape Memory Alloys

“…Consequently, several Ni-Ti-X alloy systems (where X can be Au, Pd, Pt, Hf, and Zr) have been developed to increase the transformation temperatures of binary Ni-Ti while keeping most of its outstanding properties [1]. Among these, Ni-Ti-Pd and Ni-Ti-Pt high-temperature shape memory alloys (HTSMAs) have been extensively studied in the last decade due to their high transformation temperatures and good thermal and dimensional stabilities [17][18][19]. However, the current state of the art in HTSMAs has moved to the design, processing, and characterization of cheaper alternatives such as Ni-Ti-Hf and Ni-Ti-Zr HTSMAs.…”

Investigation of microhardness evolution in an ultrafine grained NiTi alloy formed via high speed high pressure torsion (HSHPT)

“…Ni-Ti based alloys have been attractive functional materials as commercial shape memory alloys (SMAs) owing to their high strength and ductility, corrosion resistance, excellent fatigue resistance and biocompatibility [1][2][3][4]. Because of its capability to produce nanocrystalline and submicrocrystalline bulk materials, severe plastic deformation (SPD) represents one of the ways by which the properties of Ni-Ti shape memory alloys [5] can be improved.…”