Low Temperature Physics: 41, 649 (2015); https://doi.org/10.1063/1.4929593
Fizika Nizkikh Temperatur: Volume 41, Number 8 (August 2015), p. 835-847    ( to contents , go back )

Micromechanical properties of titanium VT1-0 cryorolled to various degrees of strain

A.V. Rusakova, S.V. Lubenets, L.S. Fomenko, V.A. Moskalenko, and A.R. Smirnov

B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Lenin Ave., Kharkov 61103, Ukraine
E-mail: lubenets@ilt.kharkov.ua

Received February 20, 2015, revised March 25, 2015

Abstract

Multipass rolling of titanium VT1-0 at a temperature near the liquid nitrogen temperature to the strain е = –2 resulted in the grain refinement from ~10 μm to ~35 nm and in a nearly twofold increase in microhardness. The microindentation tests showed that the cryorolled samples had a rather homogeneous structure. The enhancement of microhardness with the increment of imposed strain can be described by the modified Vоcе empirical law. The grain size dependence of microhardness in the Hall–Petch coordinates consists of two parts with the slopes kHP1 and kHP2 < kHP1, at the grain size less than ~250 nm. The strong temperature dependence of microhardness of the investigated samples suggests that their plastic deformation has a thermally activated character. Close values of the thermoactivation parameters presumably indicate the unified deformation mechanism of this material under the indenter over all grain size range.

PACS: 81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization;
PACS: 62.20.Qp Friction, tribology, and hardness;
PACS: 68.35.Gy Mechanical properties; surface strains.

Key words: titanium VT1-0, cryorolling, ultrafinegrained and nanocrystalline titanium, structur characterization, microhardness, Hall–Petch relationship, microhardness temperature dependence.

Published online: June 23, 2015

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