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Constitutive analysis of hot deformation behavior of a Ti6Al4V alloy using physical based model

journal contribution
posted on 2015-11-11, 00:00 authored by Paul Souza, Hossein BeladiHossein Beladi, R Singh, Bernard RolfeBernard Rolfe, Peter HodgsonPeter Hodgson
The effect of deformation parameters on the flow behavior of a Ti6Al4V alloy has been studied to understand the deformation mechanisms during hot compression. Cylindrical samples with partially equiaxed grains were deformed in the α+β phase region at different thermo-mechanical conditions. To develop components with tailored properties, the physically based Estrin and Mecking (EM) model for the work hardening/dynamic recovery combined with the Avrami equation for dynamic recrystallization was used to predict the flow stress at varying process conditions. The EM model revealed good predictability up to the peak strain, however, at strain rates below 0.01s-1, a higher B value was observed due to the reduced density of dislocation tangles. In contrast, the flow softening model revealed higher value of constants a and b at high strain rates due to the reduction in the volume fraction of dynamic recrystallization and larger peak strain. The predicted flow stress using the combined EM+Avrami model revealed good agreement with the measured flow stress resulted in very low average absolute relative error value. The microstructural analysis of the samples suggests the formation of coarse equiaxed grains together with the increased β phase fraction at low strain rate leads to a higher flow softening.

History

Journal

Materials science and engineering A

Volume

648

Pagination

265 - 273

Publisher

Elsevier

Location

Amsterdam, The Netherlands

ISSN

0921-5093

Language

eng

Publication classification

C Journal article; C1 Refereed article in a scholarly journal

Copyright notice

2015, Elsevier