Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7971699 | Materials Science and Engineering: A | 2018 | 24 Pages |
Abstract
A cold-rolled Ti-6Al-4V alloy was subjected to consecutive heat treatments at 1283â¯K for 1â¯h and at 823â¯K for 3â¯h in order to produce a fully lamellar microstructure. Thereafter, the material was processed by high-pressure torsion (HPT) through various numbers of turns up to a maximum of 30. It is shown that the HPT processing leads to exceptional grain refinement with average grain sizes of ~ 70 and ~ 50â¯nm after 20 and 30 turns, respectively. Tensile testing was conducted at 873 and 923â¯K with different initial strain rates using the material processed through 20 turns of HPT and this gave a maximum superplastic elongation of 820% at the relatively low temperature of 923â¯K when testing with an initial strain rate of 5.0â¯Ãâ¯10â4 sâ1. The associated strain rate sensitivity for this low temperature superplasticity was estimated as mâ¯ââ¯0.5 which is consistent with flow by grain boundary sliding.
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Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
Wenjing Zhang, Hua Ding, Pedro Henrique R. Pereira, Yi Huang, Terence G. Langdon,