Deformation behaviour of beta titanium alloy Ti–10V–4.5Fe–1.5Al in hot upset forging

Balasubrahmanyam, VV and Prasad, YVRK (2002) Deformation behaviour of beta titanium alloy Ti–10V–4.5Fe–1.5Al in hot upset forging. In: Materials Science and Engineering A, 336 (1-2). pp. 150-158.

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Abstract

The characteristics of hot deformation of a beta titanium alloy Ti–10V–4.5Fe–1.5Al have been studied by upset forging in the temperature range 650–900 °C and strain rate range $0.001–100 s^{-1}$. The true stress–true strain curves at 650 °C show continuous flow softening at strain rates above $0.1 s^{-1}$ whereas at lower strain rates, the flow stress attains a steady-state. At temperatures higher than about 750 °C, there is a distinct peak in the flow stress in the early stages of deformation followed by a steady-state at higher strains. The variation of flow stress with temperature and strain rate follows the standard kinetic rate equation at strain rates lower than about $0.1 s^{-1}$ and the apparent activation energy is estimated to be about $180\hspace{mm} kJ \hspace{2mm} mol^{-1}$. The processing map exhibited a domain in the temperature range 750–900 °C with a peak efficiency of about 48% occurring at 850 °C and $0.01 \hspace{2mm}s^{-1}$. On the basis of the microstructural features, the variation of grain size with temperature and the tensile ductility variations, the domain is interpreted to represent a process of dynamic recrystallisation (DRX). The workability is optimum under peak DRX conditions and the grain size in the DRX domain is linearly dependent on the Zener–Hollomon parameter. At strain rates higher than $10 \hspace{2mm} s^{-1}$ and in a wide temperature range, the material exhibits flow instabilities, which are manifested as flow localisation.

Item Type:	Journal Article
Publication:	Materials Science and Engineering A
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Deformation behaviour;Ti–10V–4.5Fe–1.5Al;Hot upset forging
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	09 Jul 2007
Last Modified:	20 Jan 2012 09:30
URI:	http://eprints.iisc.ac.in/id/eprint/11402

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