In-situ microstructural investigations of the TRIP-to-TWIP evolution in Ti-Mo-Zr alloys as a function of Zr concentration

Aiming at overcoming the strength-ductility trade-off in structural Ti-alloys, a new family of TRIP/TWIP Ti-alloys was developed in the past decade (TWIP: twinning-induced plasticity; TRIP: transformation-induced plasticity). Herein, we study the tunable nature of deformation mechanisms with various...

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Bibliographic Details
Published in:Journal of materials science & technology 2021-02, Vol.65, p.228-237
Main Authors: Qian, Bingnan, Zhang, Jinyong, Fu, Yangyang, Sun, Fan, Wu, Yuan, Cheng, Jun, Vermaut, Philippe, Prima, Frédéric
Format: Article
Language:English
Subjects:
Deformation mechanisms
Engineering Sciences
In-situ traction-EBSD
Metastable beta (β) Ti-alloys
TEM observation
TRIP/TWIP effects
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Summary:Aiming at overcoming the strength-ductility trade-off in structural Ti-alloys, a new family of TRIP/TWIP Ti-alloys was developed in the past decade (TWIP: twinning-induced plasticity; TRIP: transformation-induced plasticity). Herein, we study the tunable nature of deformation mechanisms with various TWIP and TRIP contributions by fine adjustment of the Zr content on ternary Ti-12Mo-xZr (x = 3, 6, 10) alloys. The microstructure and deformation mechanisms of the Ti-Mo-Zr alloys are explored by using in-situ electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The results show that a transition of the dominant deformation mode occurred, going from TRIP to TWIP major mechanism with increasing Zr content. In the Ti-12Mo-3Zr alloy, the stress-induced martensitic transformation (SIM) is the major deformation mode which accommodates the plastic flow. Regarding the Ti-12Mo-6Zr alloy, the combined deformation twinning (DT) and SIM modes both contribute to the overall plasticity with enhanced strain-hardening rate and subsequent large uniform ductility. Further increase of the Zr content in Ti-12Mo-10Zr alloy leads to an improved yield stress involving single DT mode as a dominant deformation mechanism throughout the plastic regime. In the present work, a set of comprehensive in-situ and ex-situ microstructural investigations clarify the evolution of deformation microstructures during tensile loading and unloading processes.
ISSN:1005-0302
1941-1162
DOI:10.1016/j.jmst.2020.04.078