Deformation mechanisms in a metastable beta titanium twinning induced plasticity alloy with high yield strength and high strain hardening rate
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Metastable β titanium alloys with both twinning (TWIP) and martensite transformation (TRIP)
usually exhibit a low yield strength of between 200 and 500MPa, but high strain hardening rate
and large uniform elongation. Alloys that exhibit twinning on a single system provide a higher
yield strength, but a lower strain hardening rate. Here, for the first time, we report a new alloy
(Ti-7Mo-3Cr wt%) with both high yield strength (695 MPa) and high work hardening rate
(~1900 MPa) and a substantial 33.3% uniform elongation. The deformation mechanisms were
systematically investigated using EBSD and TEM for samples strained to 1.3%, 5% and 16%.
The high yield strength was achieved through initial deformation mechanisms of two twin
systems, namely both {332}<113> and {112}<111> twinning. Importantly, the martensite
transformation was suppressed at this stage of deformation. The combination of two twin
systems, with approximately the same intensity, resulted in a high strain hardening rate
(1600MPa to 1900MPa), much greater compared to alloys that exhibit a single twin system.
Moreover, the TRIP effect was observed at strains greater than 5%, which also contributed to
the high strain hardening rate large uniform elongation.
usually exhibit a low yield strength of between 200 and 500MPa, but high strain hardening rate
and large uniform elongation. Alloys that exhibit twinning on a single system provide a higher
yield strength, but a lower strain hardening rate. Here, for the first time, we report a new alloy
(Ti-7Mo-3Cr wt%) with both high yield strength (695 MPa) and high work hardening rate
(~1900 MPa) and a substantial 33.3% uniform elongation. The deformation mechanisms were
systematically investigated using EBSD and TEM for samples strained to 1.3%, 5% and 16%.
The high yield strength was achieved through initial deformation mechanisms of two twin
systems, namely both {332}<113> and {112}<111> twinning. Importantly, the martensite
transformation was suppressed at this stage of deformation. The combination of two twin
systems, with approximately the same intensity, resulted in a high strain hardening rate
(1600MPa to 1900MPa), much greater compared to alloys that exhibit a single twin system.
Moreover, the TRIP effect was observed at strains greater than 5%, which also contributed to
the high strain hardening rate large uniform elongation.
Date Issued
2018-06-15
Date Acceptance
2018-04-14
Citation
Acta Materialia, 2018, 152, pp.301-314
ISSN
1359-6454
Publisher
Elsevier
Start Page
301
End Page
314
Journal / Book Title
Acta Materialia
Volume
152
Copyright Statement
©
201
8
Acta
Materialia
Inc.
Published
by
Elsevier
Ltd.
This
is
an
open
access
article
under
the
CC
BY
license
(http://creativecommons.org/licenses/by/4.0/).
201
8
Acta
Materialia
Inc.
Published
by
Elsevier
Ltd.
This
is
an
open
access
article
under
the
CC
BY
license
(http://creativecommons.org/licenses/by/4.0/).
Sponsor
Engineering & Physical Science Research Council (E
Grant Number
138874
Subjects
Science & Technology
Technology
Materials Science, Multidisciplinary
Metallurgy & Metallurgical Engineering
Materials Science
TRANSMISSION ELECTRON-MICROSCOPY
SPINAL FIXATION APPLICATIONS
CHANGEABLE YOUNGS MODULUS
GRAIN-ORIENTATION
PHASE-STABILITY
TWIP STEEL
TI-ALLOYS
TRANSFORMATION
BEHAVIOR
DEPENDENCE
0912 Materials Engineering
0913 Mechanical Engineering
Materials
Publication Status
Published
Date Publish Online
2018-04-17