Release Time:2019-03-12  Hits:

Indexed by: Journal Article

Date of Publication: 2018-06-01

Journal: ACTA METALLURGICA SINICA-ENGLISH LETTERS

Included Journals: SCIE

Volume: 31

Issue: 6

Page Number: 604-614

ISSN: 1006-7191

Key Words: beta-Type titanium alloy; Pre-cold rolling; Twinning deformation; Isothermal omega-phase; Strength-ductility

Abstract: This paper reported an effectiveness of pre-cold rolling-induced {332}<113> twins combined with subsequent isothermal x-phase formation for enhancement of uniform elongation in a beta-type Ti-15Mo alloy with high yield strength level. Mechanical {332}<113? twins were induced by cold rolling with an thickness reduction of 5%, which had little effect on x-phase precipitation after aging at 573 K for 3.6 ks. Twinning after the cold rolling was further activated during tensile deformation, even with the presence of isothermal omega-phase. This combination of twins and omega-phase enhanced uniform elongation from 0 to 9% at yield strength level of 890 MPa. The high yield strength was mainly dominated by dislocation slip due to the isothermal x-phase formation, and early onset of plastic instability after yielding was hindered due to the pre-cold rolling-induced twins. Dynamic microstructural refinement was induced by further twinning activation during deformation, which resulted in high work hardening rate corresponding enhancement of uniform elongation.