Stress-induced hexagonal close-packed to face-centered cubic phase transformation in commercial-purity titanium under cryogenic plane-strain compression

A rare transformation from a hexagonal close-packed (hcp) phase to a face-centered cubic (fcc) phase was found in pure Ti deformed by cryogenic channel-die compression indented for microstructural refinement. While grain refinement occurred upon recurrent intersection of the persistent slip bands, nucleation of the platelet fcc phase was identified at the areas of intersecting slip bands. The stress-induced phase transformation was attributed to the gliding of Shockley partial dislocations, resulting in < 0 0 0 1 >(hcp)//< 0 0 1 >(fcc), < 1 0 (1) over bar 0 >(hcp)//< 1 (1) over bar 0 >(fcc), and < 1 1 (2) over bar 0 >(hcp)//< 1 1 0 >(fcc) orientation relationships. (c) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.