Effect of plastic deformation on physical properties and structure of the shape memory alloy Ti49.5Ni50.5

Influence of the structure of the Ti-49.8 at % Ni alloy on its thermal expansion during the martensitic phase transformation

“…For all the considered states, the ΔL(T)/L 0 curves are the hysteresis loop [12]. During heating in the IMT process (B' B2), the sample undergoes the jump like elongation, while during cooling, the direct mar tensitic transformation (DMT) (B2 B19') leads to an abrupt shortening in its length (as shown by arrows in the curves).…”

“…The authors of [12] note that the B2 R transitions are accompanied by kinks in the ΔL(T)/L 0 curves, while R B19' transitions are accompanied by jumps.…”

“…It was shown in [12] that the temperature depen dence of thermal expansion ΔL/L 0 (T) in the tempera ture range of thermoelastic martensitic transformation B2 R B19' has the hysteresis form, which is characteristic of the first order phase transitions. The authors of [12] note that the B2 R transitions are accompanied by kinks in the ΔL(T)/L 0 curves, while R B19' transitions are accompanied by jumps.…”

Effect of plastic deformation by torsion on the heat capacity of the Ni50.5Ti49.5 alloy

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883Studies of titanium nickelide based shape memory alloys (see, e.g., [1] and references therein) show that severe plastic deformation by torsion under high pres sure (HPT) in Bridgman anvils causes the transition of the microcrystalline structure of initial samples to the amorphous-nanocrystalline state. In this case, the electronic and lattice properties of the alloys are changed substantially.

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“…According to the data of chemical analysis, the elemental composi tion of impurities in the alloy was as follows (wt %): C = 0.0372, S = 0.0001, O 2 = 0.0167, N = 0.0003. The technique of preparing the alloys was described in more detail in [1,2]. The effect of plastic deformation on the thermal expansion and the kinetic, magnetic, and optical properties of the alloy were studied in [1].…”