Microplasticity at Room Temperature in α/β Titanium Alloys

Abstract

The current understanding of room temperature microplasticity in a/b titanium alloys is reviewed with a special emphasis on dual-phase engineering alloys. As the interplay between microstructure and deformation mechanisms governs both the microscale and macroscale mechanical response, a brief description of the main features of a/b microstructures is first provided. Elastic and plastic deformation in individual phases is then described. The complex interactions that govern the effect of grain boundaries, phase interfaces and microtexture on deformation behaviour are reviewed. Crystal plasticity simulations have evolved over the past decade as a key technique to obtain a mechanistic understanding of the deformation of Ti alloys. Micromechanical aspects are emphasized with a discussion of input parameters required to achieve realistic constitutive modeling. As microplasticity is especially relevant in cyclic loading such as experienced in-service by components, the current understanding of the relation of this regime with fatigue and dwell-fatigue behavior is briefly summarized in the final section.

Tensile properties of Ti-6Al-4V as-built by laser metal deposition: The relationship between heat affected zone bands, strain localization and anisotropy in ductility

“…In order to explain the similar strengths levels along TD and LD in the SA sample, the maximum Schmid factor (SF) among basal and prismatic slip systems was calculated for each pixel of the EBSD map presented in figure 6a. These two slip modes were considered as they are the main slip systems operating in Ti-6Al-4V [62][63][64]. In addition, no weight related to the critical resolved shear stress values was introduced as they exhibit similar strengths according to a recent review [63].…”

“…These two slip modes were considered as they are the main slip systems operating in Ti-6Al-4V [62][63][64]. In addition, no weight related to the critical resolved shear stress values was introduced as they exhibit similar strengths according to a recent review [63]. The average values are 0.409 and 0.434 along TD and LD respectively.…”

The Comparation of Arrhenius-Type and Modified Johnson–Cook Constitutive Models at Elevated Temperature for Annealed TA31 Titanium Alloy

“…In addition, they are improved to 15.77% and 0.9620 through the global optimization method, respectively. The Arrhenius-type model cannot accurately represent the flow behavior using only one set of parameters for the annealed TA31, because the temperature range includes the α and α + β ranges with the different deformation mechanisms [38]. For the modified JC model in Figure 9, the predicted data can efficiently represent the flow behavior of this material under the entire experimental conditions.…”

Cold dwell behaviour of Ti6Al alloy: Understanding load shedding using digital image correlation and dislocation based crystal plasticity simulations

“…For instance, typical flight cycles comprise of takeoff (load up), cruise (stress hold) and landing (load off), and are combined with a varying temperature from ambient conditions to engine working conditions. During the cruise phase, titanium fan blades and compressor disks experience long hours of high stress hold (dwell), which often results in a drastic lifetime reduction for these titanium components [5,6,7,8,9]. This phenomenon that seems to happen at relatively lower temperatures (typically below 200 • C) has been termed "cold dwell fatigue".…”