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Enhancing Superplasticity of Ultrafine‐Grained Ti–6Al–4V without Imposing Severe Plastic Deformation
Author(s) -
Kim Daehwan,
Won Jong Woo,
Park Chan Hee,
Hong Jae Keun,
Lee Taekyung,
Lee Chong Soo
Publication year - 2019
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201800115
Subject(s) - superplasticity , materials science , severe plastic deformation , annealing (glass) , recrystallization (geology) , metallurgy , grain growth , thermomechanical processing , nanocrystalline material , torsion (gastropod) , grain size , composite material , microstructure , nanotechnology , medicine , paleontology , surgery , biology
This study proposes a new regime of thermomechanical treatment composed of temperature‐decreasing step rolling (STEP) and subsequent annealing to fabricate ultrafine‐grained Ti–6Al–4V bulk plates with enhanced superplastic properties. This method utilizes fine martensites as an initial structure to assist in effective grain refinement even without imposing severe plastic deformation. The processed STEP alloys exhibit significant elongation of 706–856% at elevated temperatures. In particular, subsequent annealing at 600 °C induces superplasticity comparable to that obtained by high‐pressure torsion. This is attributed to the acceleration of continuous dynamic recrystallization. The developed thermomechanical process has the advantage of mass‐productivity in contrast to the existing SPD techniques.