TY - JOUR

T1 - Features of Multistage Thermoelastic B2–R–B19′ Martensitic Transformations in Heterophase Single Crystals of Ti–Ni Alloys

AU - Panchenko, E. Yu

AU - Chumlyakov, Yu I.

AU - Maier, H.

N1 - Publisher Copyright: © 2014, Springer Science+Business Media New York. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2014/12/4

Y1 - 2014/12/4

N2 - In heterophase Ti50.0–xNi50.0+x (х = 0.8–1.0 at.%) single crystals after aging at 823 K for 1.5 h at the heating/cooling rate (15 ± 1) K/min and stepwise aging at 823 K for 1.5 h plus aging at 573–623 K for 1 h, multi-stage martensitic transformations are observed: there are three peaks of heat release in the DSC (differential scanning calorimetry) curves. The first peak is associated with a B2–R-transformation and increased electrical resistance ρ and the other two correspond to the development of an R–B19′-martensitic transformation occurring in two stages, and are followed by a two-stage drop of electrical resistance in the ρ(T) plot. The high-temperature stage of the R–B19′-martensitic transition is associated with transformations under the action of local stress fields in the vicinity of disperse Ti3Ni4 particles measuring ~400 nm, while the low-temperature stage is associated with transformations in the spaces between large particles containing fine disperse β′-phase particles isostructural with respect to the matrix, measuring 3–5 nm, which are formed during slow cooling from 823 K or in the course of low-temperature aging at 573–623 K.

AB - In heterophase Ti50.0–xNi50.0+x (х = 0.8–1.0 at.%) single crystals after aging at 823 K for 1.5 h at the heating/cooling rate (15 ± 1) K/min and stepwise aging at 823 K for 1.5 h plus aging at 573–623 K for 1 h, multi-stage martensitic transformations are observed: there are three peaks of heat release in the DSC (differential scanning calorimetry) curves. The first peak is associated with a B2–R-transformation and increased electrical resistance ρ and the other two correspond to the development of an R–B19′-martensitic transformation occurring in two stages, and are followed by a two-stage drop of electrical resistance in the ρ(T) plot. The high-temperature stage of the R–B19′-martensitic transition is associated with transformations under the action of local stress fields in the vicinity of disperse Ti3Ni4 particles measuring ~400 nm, while the low-temperature stage is associated with transformations in the spaces between large particles containing fine disperse β′-phase particles isostructural with respect to the matrix, measuring 3–5 nm, which are formed during slow cooling from 823 K or in the course of low-temperature aging at 573–623 K.

KW - disperse particles

KW - single crystals

KW - thermoelastic martensitic transformations

UR - http://www.scopus.com/inward/record.url?scp=84925543285&partnerID=8YFLogxK

U2 - 10.1007/s11182-014-0352-1

DO - 10.1007/s11182-014-0352-1

M3 - Article

AN - SCOPUS:84925543285

VL - 57

SP - 1116

EP - 1125

JO - Russian physics journal

JF - Russian physics journal

SN - 1064-8887

IS - 8

ER -