Investigating the heat resistant properties of the TiNi shape memory alloy on the B19′→B2 phase transformation using the alloy powder

Comparative study on the high-temperature oxidation resistance of porous and solid TiNi-based alloys

“…The proposed routes for the decomposition of TiNi during oxidation do not contradict the data reported by other authors and remain largely consistent with the TiNi phase diagram for equiatomic composition nearby 1000 °C [13,14,19,34]. During high-temperature corrosion in air, the thickness of the oxidized layer increases drastically.…”

“…Oxygen diffusion through the TiO 2 layer is inhibited at ambient temperature, but growth in temperature changes the stresses in the oxide layer, increases its permeability, decreases the protective ability and stability [16,17]. Under high-temperature exposure, the protective layer is able to crack and peel, becoming prone to corrosion and leading to an easier release of toxic Ni ions [8,[18][19][20]. Of course, the duration and temperature of heat treatment affect the quantitative and qualitative composition of the oxidized surface.…”

“…Comparative analysis of TiNi-based alloys (porous and solid) subjected to high-temperature oxidation, where, in particular, the specific role of incipient surface constituents prone to corrosion is evaluated, has not been done so far. However, there are a few controversial reports on the oxidation of TiNi in the temperature range of 300 °C-1000 °C [6,10,13,14,19,20].…”

“…Oxidative behaviors of TiNi alloys were reported at temperatures below and above 450 °C-500 °C [14,19]. When heated to 500 °C, TiO and Ni are detected on the surface, and at a temperature above 600 C, a multilayer structure of TiO 2 , Ni, and Ni 3 Ti was found.…”

Grain structure orientational change in Ti6Al4V alloys induced by sea water quenching and novel stress relief annealing process

“…Furthermore, a monoclinic structure with a = 4.4566 Å; b = 3.0022 Å; c = 4.4760 Å formed attributable to stress induced by high cooling rates. This monoclinic phase is different from the monoclinic phase common in alloys such as TiNi [49]. Upon annealing at 900 • C, two HCP crystal structures and a monoclinic phase with different lattice parameters (a = 4.0614 Å; b = 6.4476 Å; c = 2.6582 Å) were detected.…”