Features of Duplex Microstructural Evolution and Mechanical Behavior in the Titanium Alloy Processed by Equal-Channel Angular Pressing

Authors: Semenova, I.P., Dyakonov, G.S., Raab, G.I., Grishina, Y.F., Huang, Y., Langdon, T.G.

Journal: Advanced Engineering Materials

Publication Date: 01/08/2018

Volume: 20

Issue: 8

eISSN: 1527-2648

ISSN: 1438-1656

DOI: 10.1002/adem.201700813

Abstract:

This report describes a study of the regularities in the kinetics of microstructure evolution and recrystallization processes in the Ti–5.7Al–3.8Mo–1.2Zr–1.3Sn alloy (Russian analogue VT8M-1) during processing by equal-channel angular pressing (ECAP). To produce a duplex (globular-lamellar) structure, the billets are subjected to preliminary heat treatment, including water-quenching from a temperature below the β-transus followed by annealing at 700 °С. For the ECAP temperature selection, the deformation behavior of the alloy with a duplex structure is investigated under upsetting in the temperature range of 650–800 °С. The evolution of the globular and lamellar fractions is examined during ECAP processing, and an emphasis is placed on the role of phase transformations, dynamic recrystallization, and spheroidization of the α-phase which is realized with increasing accumulated strain when processing by ECAP. It is demonstrated that after 6 ECAP passes an equiaxed ultrafine-grained structure is formed with a mean α-phase grain/subgrain size of ≈0.6 μm. The investigation includes an examination of the effect of microstructure on the mechanical properties of the alloy.

https://eprints.bournemouth.ac.uk/33439/

Source: Scopus