Microstructure and Crystallography of α Phase Nucleated Dynamically during Thermo‐Mechanical Treatments in Metastable β Titanium Alloy

Abstract

The a phase nucleated dynamically during the thermo-mechanical coupling process in titanium alloy is really interesting but difficult to sufficiently ascertain. In the present work, the a phase nucleation behavior, the orientation relationship between a/b as well as the phase transformation kinetics during hot deformation of Ti-5553 alloy were investigated in-depth. Results reveal that the "necklace" microstructure formed. The Burgers orientation relationship between a/b phases has been destroyed gradually. The b ! a phase transformation is obviously retarded during the hot compression due to the competitive effect of softening process (dynamic recovery/recrystallization). These results could provide valuable reference for process optimization and the microstructural evolution controlling.

Formation of slip bands and microstructure evolution of Ti-5Al-5Mo-5V-3Cr-0.5Fe alloy during warm deformation process

“…Compared with the results of high temperature deformation at 800°C in Ref. [38], there is no significant change in the deformation mechanism of Ti-5553 alloy.…”

“…Furthermore, the dislocation slip systems are controlled by thermally-activated process. That is why dislocation slip is the predominant hot deformation mode in metastable β titanium alloys, whether deformation at the high temperature (for example 800°C [38]) and lower 600°C) or room temperature. The slip as a predominant deformation mechanism was also observed in other Ti-alloys by S. Hanada et al [40].…”

Hot Deformation Behavior of a Novel Near-β Titanium Alloy Ti-5.5Mo-6V-7Cr-4Al-2Sn-1Fe in (α+β) Phase Region

“…Their results indicated that the deformation bands and dislocations generation during the thermal deformation process increased the nucleation sites of α phase and promoted the β→ α transition. Fan et al (2017) explained the spheroidization mechanism of α phase of Ti-7333 alloy during thermal deformation. However, Jonas et al (2017) found that flow stress reached a peak after thermal deformation and then decreased gradually, and the content of β phase increased.…”

Grain morphology and texture evolution of TC21 titanium alloy during annealing with different time

“…Titanium and its alloys have a wide range of applications, including aerospace, biomedicine and transportation industries, due to their excellent mechanical properties [1][2][3]. The microstructure is a key factor determining the mechanical properties [4,5]. It is well known that the lamellar microstructure of titanium alloy has moderate strength and fatigue crack growth resistance but low ductility, while the equiaxed microstructure presents a better balance of strength and ductility [6].…”