High-temperature flow characterization and microstructural evolution of Ti6242 alloy: Yield drop phenomenon

Rezaee, Mohammad; Zarei-Hanzaki, A.; Mohamadizadeh, Alireza; Ghasemi, E.

doi:10.1016/j.msea.2016.07.043

Cited by 28 publications

(12 citation statements)

References 32 publications

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“…From microscopic examination, the plastically deformed zone (PDZ)—covering the combined thickness of the CWZ and TMAZ—was ~500 µm for both the Ti-64 and Ti-6242 sides. This may be attributed to the similar high temperature strength of Ti-6242 and Ti-64 [ 50 , 51 ], as well as their comparable temperature-dependent thermal conductivity behavior and values [ 52 , 53 , 54 , 55 ]. Previously in the work of Guo et al [ 31 ] on LFW of Ti-64 to Ti-6246, the size of the PDZ was also similar, at about 1.5 mm on either side of the weld line.…”

Section: Resultsmentioning

confidence: 99%

“…It is worth mentioning that the impact of this soft metastable/retained β phase in the TMAZ/HAZ of AWed dissimilar alloy joints is thought to be less adverse than the In general, previous studies on LFW of similar titanium alloys have also indicated hardness peaks in the CWZ and reported hardness increases of 18-40% in the AWed condition relative to the as-received PM (Table 4). Of greater controversy has been the TMAZ and/or HAZ hardness values, which were reported to be in-between those of the CWZ and PM [15,39,51,[77][78][79] or lower than the PM [16,17,39,53,79]. Grujicic et al [62] attributed the lower hardness in the TMAZ/HAZ to grain coarsening.…”

Section: Hardnessmentioning

confidence: 99%

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Joining of Dissimilar Alloys Ti-6Al-4V and Ti-6Al-2Sn-4Zr-2Mo-0.1Si Using Linear Friction Welding

et al. 2020

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Dissimilar joints between Ti-6Al-4V (Ti-64) and Ti-6Al-2Sn-4Zr-2Mo-0.1Si (Ti-6242) were manufactured using linear friction welding. The weld quality, in terms of the microstructure and mechanical properties, was investigated after stress relief annealing (SRA) at 750 °C for 2 h and compared with the as-welded (AWed) results. The central weld zone (CWZ) microstructure in the AWed condition consisted of recrystallized prior-β grains with α’ martensite, which transformed into an acicular α+β structure after SRA. The hardness in the AWed condition was highest in the CWZ and decreased sharply through the thermomechanically affected zones (TMAZ) to the parent materials (PMs). After SRA, the hardness of the CWZ decreased, mainly due to tempering of the α’ martensite microstructure. Static tensile testing of the dissimilar welds in both the AWed and stress relief annealed (SRAed) conditions resulted in ductile fracture occurring exclusively in the Ti-6Al-4V side of the joint. The promising results on joining of Ti-64 to Ti-6242 provide valuable insight for tailoring performance of next-generation aero-engine products.

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Section: Resultsmentioning

confidence: 99%

Section: Hardnessmentioning

confidence: 99%

Joining of Dissimilar Alloys Ti-6Al-4V and Ti-6Al-2Sn-4Zr-2Mo-0.1Si Using Linear Friction Welding

et al. 2020

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“…For these conditions, the yield drop phenomenon is systematically detected. As suggested by Sandstrom et al [38] and Rezaee et al [39], the yield drop phenomenon is therefore likely due to dynamic recrystallization. Specifically, the growth of recrystallized grains, with a low dislocation content, is associated with a rapid decrease in the yield stress.…”

Section: B-treated Ti17 Alloymentioning

confidence: 75%

Impact of the initial microstructure and the loading conditions on the deformation behavior of the Ti17 titanium alloy

et al. 2019

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In this work, the impact of the microstructure and the loading conditions on the mechanical behavior of a brich Ti17 titanium alloy is investigated. For this purpose, two different initial microstructures are considered : (i) a two-phase lamellar a ? b microstructure and (ii) a single-phase equiaxed b-treated microstructure. First, compression tests are performed at different strain rates (from 10 À1 to 10 s-1) and different temperatures (from 25 to 900 C) for both microstructures. Then, optical microscopy, scanning electron microscopy, EBSD and X-ray diffraction analyses of deformed specimens are carried out. Whatever the loading conditions are, the flow stress of the as-received a ? b Ti17 is higher than that of the b-treated Ti17. Also, because of a higher strain-rate sensitivity, the b-treated Ti17 is less prone to shear banding. At low temperatures (i.e., T 450 C), the deformation behavior of both the as-received a ? b and the b-treated Ti17 is controlled by strain hardening. For the b-treated Ti17 alloy, martensitic transformation is systematically detected in this temperature range. The softening behavior of the as-received a ? b Ti17 observed at high temperatures is due to the joint effect of dynamic recrystallization, dynamic transformation , adiabatic heating and morphological texture evolution. For the b-treated Ti17 alloy, when the temperature exceeds 700 C, stressstrain curves display a yield drop phenomenon, which is explained by dynamic recrystallization.

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“…For these conditions, a steady-state flow stress behavior is systematically detected. As suggested by [52,53], the steady-state flow stress can be related to dynamic recrystallization. According to Figure 15, a strong change of the crystallographic orientation of deformed Ti42Nb alloy is observed.…”

Section: Metallographic Analysismentioning

confidence: 97%

Impact of the Loading Conditions and the Building Directions on the Mechanical Behavior of Biomedical β-Titanium Alloy Produced In Situ by Laser-Based Powder Bed Fusion

et al. 2022

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In order to simulate micromachining of Ti-Nb medical devices produced in situ by selective laser melting, it is necessary to use constitutive models that allow one to reproduce accurately the material behavior under extreme loading conditions. The identification of these models is often performed using experimental tension or compression data. In this work, compression tests are conducted to investigate the impact of the loading conditions and the laser-based powder bed fusion (LB-PBF) building directions on the mechanical behavior of β-Ti42Nb alloy. Compression tests are performed under two strain rates (1 s−1 and 10 s−1) and four temperatures (298 K, 673 K, 873 K and 1073 K). Two LB-PBF building directions are used for manufacturing the compression specimens. Therefore, different metallographic analyses (i.e., optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), electron backscatter diffraction (EBSD) and X-ray diffraction) have been carried out on the deformed specimens to gain insight into the impact of the loading conditions on microstucture alterations. According to the results, whatever the loading conditions are, specimens manufactured with a building direction of 45∘ exhibit higher flow stress than those produced with a building direction of 90∘, highlighting the anisotropy of the as-LB-PBFed alloy. Additionally, the deformed alloy exhibits at room temperature a yielding strength of 1180 ± 40 MPa and a micro-hardness of 310 ± 7 HV0.1. Experimental observations demonstrated two strain localization modes: a highly deformed region corresponding to the localization of the plastic deformation in the central region of specimens and perpendicular to the compression direction and an adiabatic shear band oriented with an angle of ±45 with respect to same direction.

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High-temperature flow characterization and microstructural evolution of Ti6242 alloy: Yield drop phenomenon

Cited by 28 publications

References 32 publications

Joining of Dissimilar Alloys Ti-6Al-4V and Ti-6Al-2Sn-4Zr-2Mo-0.1Si Using Linear Friction Welding

Joining of Dissimilar Alloys Ti-6Al-4V and Ti-6Al-2Sn-4Zr-2Mo-0.1Si Using Linear Friction Welding

Impact of the initial microstructure and the loading conditions on the deformation behavior of the Ti17 titanium alloy

Impact of the Loading Conditions and the Building Directions on the Mechanical Behavior of Biomedical β-Titanium Alloy Produced In Situ by Laser-Based Powder Bed Fusion

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