TY - JOUR

T1 - Martensite stabilisation effect in Ni-rich NiTi shape memory alloy with different structure and martensitic transformations

AU - Belyaev, Sergey

AU - Resnina, Natalia

AU - Rakhimov, Timur

AU - Андреев, В.А.

PY - 2020/4/15

Y1 - 2020/4/15

N2 - The aim of the present work was to study the martensite stabilisation effect in Ni51Ti49 alloy with different structures and martensitic transformations. The quenched Ni51Ti49 alloy underwent the B2→B19’ transformation, whereas the B2→R→B19’ transformation occurred in the annealed sample. The martensite stabilisation effect was studied after deformation in the B19’ state in both samples, and in the R state in the annealed sample. It was found that despite the sample structure, no plastic strain appeared during deformation up to 7%, however, the martensite stabilisation effect was observed in both the quenched and annealed samples. If deformation occurred due to the reorientation of the R phase, the martensite stabilisation effect was negligible and did not exceed 1 °C. If the stress induced B19’ phase appeared during deformation in the R state, the martensite stabilisation effect occurred. It was found that the shift in the reverse transformation temperatures on heating of the pre-deformed sample, depended on the structure of the B19’ phase. It was assumed that the damage to the interface coherency resulted in the appearance of an additional energy barrier that influenced the finish temperature of the reverse transformation. Furthermore, it was believed that the martensite reorientation during deformation changed the stored elastic energy, and the shift in the start temperature of the reverse transformation was due to the change in the stored elastic energy and loss in the interface coherency.

AB - The aim of the present work was to study the martensite stabilisation effect in Ni51Ti49 alloy with different structures and martensitic transformations. The quenched Ni51Ti49 alloy underwent the B2→B19’ transformation, whereas the B2→R→B19’ transformation occurred in the annealed sample. The martensite stabilisation effect was studied after deformation in the B19’ state in both samples, and in the R state in the annealed sample. It was found that despite the sample structure, no plastic strain appeared during deformation up to 7%, however, the martensite stabilisation effect was observed in both the quenched and annealed samples. If deformation occurred due to the reorientation of the R phase, the martensite stabilisation effect was negligible and did not exceed 1 °C. If the stress induced B19’ phase appeared during deformation in the R state, the martensite stabilisation effect occurred. It was found that the shift in the reverse transformation temperatures on heating of the pre-deformed sample, depended on the structure of the B19’ phase. It was assumed that the damage to the interface coherency resulted in the appearance of an additional energy barrier that influenced the finish temperature of the reverse transformation. Furthermore, it was believed that the martensite reorientation during deformation changed the stored elastic energy, and the shift in the start temperature of the reverse transformation was due to the change in the stored elastic energy and loss in the interface coherency.

KW - Heat treatment

KW - Martensite stabilisation effect

KW - Martensitic transformation

KW - NiTi alloy

KW - Shape memory effect

KW - THERMODYNAMICS

KW - MECHANISM

KW - STRESS

KW - DEFORMATION

KW - REORIENTATION

UR - http://www.scopus.com/inward/record.url?scp=85081020744&partnerID=8YFLogxK

U2 - 10.1016/j.sna.2020.111911

DO - 10.1016/j.sna.2020.111911

M3 - Article

AN - SCOPUS:85081020744

VL - 305

JO - Sensors and Actuators, A: Physical

JF - Sensors and Actuators, A: Physical

SN - 0924-4247

M1 - 111911

ER -