The room temperature tensile deformation behavior of thermomechanically processed β-metastable Ti-Nb-Ta-Zr bio-alloy: the role of deformation-induced martensite

Microstructure and Mechanical Properties of Ti-35Nb-2Ta-3Zr Alloy by Laser Quenching

“…As can be seen from the profile, there are β phase peaks and α ′′ martensite peaks. Compared to the five or six martensites diffraction peaks during the cold rolling process (Guo et al, 2007;Wang et al, 2008a,c;Maghsoudlou et al, 2018), the number of martensite peak after laser quenching is very small. This may be the result of fast heating and cooling rates during laser quenching, which allow only a short time for phase transformations (Konstantino and Altus, 1999).…”

“…α ′′ martensite transformation is very important in β-titanium alloys, which not only grants superelastic properties, but also accommodates both elastic and plastic strains (Maghsoudlou et al, 2018;Yang et al, 2018). In previous researches (Lai et al, 2018;Maghsoudlou et al, 2018), stress-induced martensitic transformation occurred in the early stage of plastic deformation of β titanium alloys, causing the yielding phenomenon. And the yield strength value is equivalent to the critical stress value of the induced β → α ′′ martensite transformation.…”

“…In Figure 4B, significantly deformed microstructures and high-density dislocation tangles were found (as indicated by the white arrow). This phenomenon can be seen in many mechanical processes (Min et al, 2012;Lin et al, 2013;Liu et al, 2015;Wang et al, 2017;Lai et al, 2018;Maghsoudlou et al, 2018), and the dislocation tangles had a bad influence on phase transformation, leading to more martensite nucleation than martensite propagation. Therefore, the number of martensite detected is small, which should be due to the dislocation tangles.…”

“…Recently, a variety of deformation mechanisms in β titanium alloys have been found, including stress-induced phase transformations (β → α ′ , β → α ′′ or β → ω) (Ozan et al, 2017;Wang et al, 2017;Lai et al, 2018;Maghsoudlou et al, 2018;Yang et al, 2018;Gao et al, 2019), {332} twinning (Tobe et al, 2014;Lai et al, 2016Lai et al, , 2018Gao et al, 2019), {112} twinning (Yao et al, 2017;Gao et al, 2018), as well as dislocation slip (Lai et al, 2018;Gao et al, 2019). It was also revealed that the dislocation slip dominates the plastic deformation in the β-titanium alloys with higher stability, while reducing the stability of the β-titanium alloys activates other deformation mechanisms such as deformation twins and martensite transformation (Lai et al, 2016;Maghsoudlou et al, 2018). Generally, phase transformation, twins or dislocation slip can be activated individually or simultaneously, which strongly influence the mechanical properties during processing.…”

“…Min et al (2012) found that that the combination of twinning and slip in Ti-Mo-based alloys, can enhance the uniform elongation and maintain high strength. In addition, it was reported that the stress-induced α" martensitic during cold rolling contributed to the spectacular work hardening behavior, resulting in super elastic and pseudo-elastic zones of the tensile stress-strain curves, and reduce the elastic shear modulus (Wang et al, 2008a(Wang et al, , 2009bMaghsoudlou et al, 2018).…”