TY - JOUR

T1 - Thermal cycling stability of the B2 ←→ B19’ transformation in the Ti-Hf-Ni-Cu alloys with cast and ultrafine-grained structures

AU - Реснина, Наталья Николаевна

AU - Беляев, Сергей Павлович

AU - Базлов, Андрей Игоревич

AU - Сибирев, Алексей Владимирович

AU - Иванов, Алексей Максимович

AU - Поникарова, Ирина Викторовна

AU - Трофимова, Марина Евгеньевна

AU - Бикбаев, Рашид Менналиевич

AU - Орлов, Владимир Евгеньевич

AU - Данилов, Денис Васильевич

PY - 2025/3/1

Y1 - 2025/3/1

N2 - Martensitic transformations were studied during thermal cycling of Ti40.7 Hf9.5 Ni44.8 Cu5 and Ti40.7 Hf9.5 Ni39.8 Cu10 alloys with cast and ultrafine-grained structures the latter being formed by crystallization of amorphous ribbons. The variation of transformation temperatures and resistivity were analyzed over 500 thermal cycles through the temperature range of martensitic transformation. The results showed that in the samples with cast structure, transformation temperatures significantly decreased with the number of cycles, while in ribbons with ultrafine-grained structure, all transformation temperatures were constant. In Ti40.7 Hf9.5 Ni44.8 Cu5 ribbons, the variation in resistivity was significantly less than in the cast samples, while in the Ti40.7 Hf9.5 Ni39.8 Cu10 alloy the ρ(N) curves were comparable. This is due to the fact that yield limit for dislocation slip in Ti40.7 Hf9.5 Ni44.8 Cu5 ribbons was twice larger than in the cast state, hence the dislocation density in ribbon sample was hardly changed on thermal cycling while it increased in the cast sample. In Ti40.7 Hf9.5 Ni39.8 Cu10 alloy the dislocation yield limit was the same in ribbons and cast samples, hence, the dislocation density increased on thermal cycling in the same way. As the transformation temperatures were constant in ribbon samples of both alloys, then one may conclude that the value of the dislocation yield limit and the variation in dislocation density on thermal cycling had no effect on the variation in transformation temperatures. It was assumed that a high thermal cycling stability of the martensitic transformation in ribbon samples were due to only one plate with corresponding variant pairs of martensite twins formed in each grain on cooling.

AB - Martensitic transformations were studied during thermal cycling of Ti40.7 Hf9.5 Ni44.8 Cu5 and Ti40.7 Hf9.5 Ni39.8 Cu10 alloys with cast and ultrafine-grained structures the latter being formed by crystallization of amorphous ribbons. The variation of transformation temperatures and resistivity were analyzed over 500 thermal cycles through the temperature range of martensitic transformation. The results showed that in the samples with cast structure, transformation temperatures significantly decreased with the number of cycles, while in ribbons with ultrafine-grained structure, all transformation temperatures were constant. In Ti40.7 Hf9.5 Ni44.8 Cu5 ribbons, the variation in resistivity was significantly less than in the cast samples, while in the Ti40.7 Hf9.5 Ni39.8 Cu10 alloy the ρ(N) curves were comparable. This is due to the fact that yield limit for dislocation slip in Ti40.7 Hf9.5 Ni44.8 Cu5 ribbons was twice larger than in the cast state, hence the dislocation density in ribbon sample was hardly changed on thermal cycling while it increased in the cast sample. In Ti40.7 Hf9.5 Ni39.8 Cu10 alloy the dislocation yield limit was the same in ribbons and cast samples, hence, the dislocation density increased on thermal cycling in the same way. As the transformation temperatures were constant in ribbon samples of both alloys, then one may conclude that the value of the dislocation yield limit and the variation in dislocation density on thermal cycling had no effect on the variation in transformation temperatures. It was assumed that a high thermal cycling stability of the martensitic transformation in ribbon samples were due to only one plate with corresponding variant pairs of martensite twins formed in each grain on cooling.

KW - TiNi-based alloys

KW - martensitic transformation

KW - shape memory alloys

KW - thermal cycling stability

KW - thin ribbon

UR - https://www.mendeley.com/catalogue/b312f7dc-b8a1-3ecf-b266-ce4766fba884/

U2 - 10.48612/letters/2025-1-8-14

DO - 10.48612/letters/2025-1-8-14

M3 - Article

VL - 15

SP - 8

EP - 14

JO - Letters on Materials

JF - Letters on Materials

SN - 2218-5046

IS - 1

ER -