TY - JOUR

T1 - Variation in Martensitic Transformation Temperatures and Defect Density upon Thermal Cycling of Ti-Hf-Ni-Cu Alloys with Various Grain Sizes

AU - Беляев, Сергей Павлович

AU - Реснина, Наталья Николаевна

AU - Поникарова, Ирина Викторовна

AU - Сибирев, Алексей Владимирович

AU - Иванов, Алексей Максимович

AU - Бикбаев, Рашид Менналиевич

AU - Трофимова, Марина Евгеньевна

AU - Базлов, Андрей Игоревич

PY - 2026/2/25

Y1 - 2026/2/25

N2 - Abstract: The variation in martensitic transformation temperatures, electrical resistivity, and dislocation density were studied during 500 thermal cycles in Ti40.7Hf9.5Ni44.8Cu5 alloy with grain sizes ranging from 130 to 0.16 µm. The maximum transformation temperature change was observed in the sample with an average grain size of 130 µm, and the minimum temperature change was found in the sample with a grain size of 0.16 µm. It was shown that during thermal cycling of Ti40.7Hf9.5Ni44.8Cu5 alloy the transformation temperatures can decrease, increase, or remain constant, independently of the grain size. Analysis of the dislocation density variation measured by the Williamson–Hall method and the resistivity variation determined in the austenitic and martensitic states showed that these quantities change nonmonotonically with increasing number of thermal cycles. In Ti40.7Hf9.5Ni44.8Cu5 samples with grain sizes of 16 and 0.16 µm, the dislocation density and resistivity increased during the first 50–200 cycles and then decreased, without any effect on the transformation temperature variation. The obtained results show that the change in dislocation density is not the only reason for the change in transformation temperatures during thermal cycling.

AB - Abstract: The variation in martensitic transformation temperatures, electrical resistivity, and dislocation density were studied during 500 thermal cycles in Ti40.7Hf9.5Ni44.8Cu5 alloy with grain sizes ranging from 130 to 0.16 µm. The maximum transformation temperature change was observed in the sample with an average grain size of 130 µm, and the minimum temperature change was found in the sample with a grain size of 0.16 µm. It was shown that during thermal cycling of Ti40.7Hf9.5Ni44.8Cu5 alloy the transformation temperatures can decrease, increase, or remain constant, independently of the grain size. Analysis of the dislocation density variation measured by the Williamson–Hall method and the resistivity variation determined in the austenitic and martensitic states showed that these quantities change nonmonotonically with increasing number of thermal cycles. In Ti40.7Hf9.5Ni44.8Cu5 samples with grain sizes of 16 and 0.16 µm, the dislocation density and resistivity increased during the first 50–200 cycles and then decreased, without any effect on the transformation temperature variation. The obtained results show that the change in dislocation density is not the only reason for the change in transformation temperatures during thermal cycling.

KW - TiNi alloys

KW - dislocation density

KW - grain size

KW - martensitic transformations

KW - thermal cycling stability

UR - https://www.mendeley.com/catalogue/ba82c397-318c-395f-aa73-d3d0ff7a78c3/

U2 - 10.1134/s1029959924602069

DO - 10.1134/s1029959924602069

M3 - Article

VL - 29

SP - 103

EP - 114

JO - Physical Mesomechanics

JF - Physical Mesomechanics

SN - 1029-9599

IS - 1

ER -