The ω phase transformation during the low temperature aging and low rate heating process of metastable β titanium alloys

Tang, Bin; Chu, Yudong; Zhang, Mengqi; Meng, Caisi; Fan, Jiangkun; Kou, Hongchao; Li, Jinshan

doi:10.1016/j.matchemphys.2019.122125

Cited by 27 publications

(12 citation statements)

References 35 publications

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“…In the case of Ti-6246 alloy, it was showed that the microhardness can vary from 300 to 550 HV as a function of ageing treatment temperature and duration [50,51]. Another important transformation that can occur is represented by the β-Ti → ω-Ti phase transformation [53][54][55][56]. The ω-Ti phase shows a fine nanometre-size particles dispersion within the parent β-Ti phase, increasing strength and decreasing ductility properties (strengthening effects) and inducing important embrittlement [57][58][59][60].…”

Section: Mechanical Behaviour During Tm Processing Of Ti-6246 Alloymentioning

confidence: 99%

Microstructure and Mechanical Properties Evolution during Solution and Ageing Treatment for a Hot Deformed, above β-transus, Ti-6246 Alloy

Alluaibi

Cojocaru

Rusea³

et al. 2020

Metals

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The present study investigates the influence of hot-deformation, above β-transus and different thermal treatments on the microstructural and mechanical behaviour of a commercially available Ti-6246 titanium-based alloy, by SEM (scanning electron microscopy), tensile and microhardness testing techniques. The as-received Ti-6246 alloy was hot-deformed—HR by rolling, at 1000 °C, with a total thickness reduction (total deformation degree) of 65%, in 4 rolling passes. After HR, different thermal (solution—ST and ageing—A) treatments were applied in order to induce changes in the alloy’s microstructure and mechanical behaviour. The applied solution treatments (ST) were performed at temperatures below and above β-transus (α → β transition temperature; approx. 935 °C), to 800 °C, 900 °C and 1000 °C respectively, while ageing treatment at a fixed temperature of 600 °C. The STs duration was fixed at 27 min while A duration at 6 h. Microstructural characteristics of all thermomechanical (TM) processed samples and obtained mechanical properties were analysed and correlated with the TM processing conditions. The microstructure analysis shows that the applied TM processing route influences the morphology of the alloy’s constituent phases. The initial AR microstructure shows typical Widmanstätten/basket-weave-type grains which, after HR, are heavily deformed along the rolling direction. The STs induced the regeneration of α-Ti and β-Ti phases, as thin alternate lamellae/plate-like structures, showing preferred spatial orientation. Also, the STs induced the formation of α′-Ti/α″-Ti martensite phases within parent α-Ti/β-Ti phases. The ageing treatment (A) induces reversion of α′-Ti/α″-Ti martensite phases in parent α-Ti/β-Ti phases. Mechanical behaviour showed that both strength and ductility properties are influenced, also, by applied TM processing route, optimum properties being obtained for a ST temperature of 900 °C followed by ageing (ST2 + A state), when both strength and ductility properties are at their maximum (σUTS = 1279 ± 15 MPa, σ0.2 = 1161 ± 14 MPa, εf = 10.1 ± 1.3%).

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Section: Mechanical Behaviour During Tm Processing Of Ti-6246 Alloymentioning

confidence: 99%

Microstructure and Mechanical Properties Evolution during Solution and Ageing Treatment for a Hot Deformed, above β-transus, Ti-6246 Alloy

Alluaibi

Cojocaru

Rusea³

et al. 2020

Metals

View full text Add to dashboard Cite

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“…Ti alloys can be developed and classified using different criteria including: (1) the identification of the phases composing the material manufactured using a process that guarantees near-equilibrium cooling conditions [32,33], (2) through the quantification of the molybdenum equivalent (MoE) parameters, which takes into account the stabilisation strength of each alloying elements added [9,34], or (3) through the concept of ''bond order/d-orbital energy'' (Bo-Md) maps [35,36]. Aiming to clarify the nature of the sintered ternary Ti-Mn-Fe alloys, Table 1 and Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The alloying elements added to Ti are classified as neutral, a-stabilisers or b-stabilisers. The a-stabilising elements extend the a-phase field to higher temperatures, while the b-stabilising elements shift the b-phase field to lower temperatures, and neural elements have minor influence on the b transus temperature [9,10]. b-stabilising elements are subdivided into isomorphous b and eutectoid b elements.…”

Section: Introductionmentioning

confidence: 99%

Titanium alloys developed on the basis of the addition of cheap strong eutectoid β-stabilisers

et al. 2023

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Historically, titanium alloys have been developed disregarding the addition of eutectoid β-stabilisers as they generally lead to the formation of brittle intermetallic phases upon solidification of the alloy. However, such phenomenon can be prevented using powder metallurgy. Thus, this study considered the concurrent addition of cheap strong eutectoid β-stabilisers, namely Mn and Fe, for the development of new ternary Ti–Mn–Fe alloys, reducing the intrinsic cost of Ti alloys. It is found that the progressive addition of Mn and Fe in equal concentration enhances the densification of Ti during sintering, leading to lower amount of residual porosity, the transformation of the microstructure from purely lamellar to metastable, and the associated refinement of the microstructural features (grains and lamellae), as well as the stabilisation of a greater amount of β phase, and the formation of the metastable α″ phase. Such microstructural changes result in the strengthening (higher yield and ultimate tensile strength and hardness) and embrittlement of the alloy by changing the fundamental strain hardening mechanism of the ternary Ti–Mn–Fe alloys.

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“…04-002-8708 [60]. Thus, based on Figure 3, it can be stated that XRD analysis demonstrates the βstabilizing character of the alloying elements used (~42% in total, without oxygen), even after the application of SPD (Figure 3c) or ST (Figure 3d,e) during which there is a risk of secondary precipitation such as α, α , ω, or α"-martensite, which may endanger the mechanical properties by increasing the fragility/resilience [61][62][63][64]. These phases are unfavorable to the processability of the material.…”

Section: Micro-structural Analysis Of the Studied Alloymentioning

confidence: 94%

Tailoring a Low Young Modulus for a Beta Titanium Alloy by Combining Severe Plastic Deformation with Solution Treatment

et al. 2021

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The present paper analyzed the microstructural characteristics and the mechanical properties of a Ti–Nb–Zr–Fe–O alloy of β-Ti type obtained by combining severe plastic deformation (SPD), for which the total reduction was of εtot = 90%, with two variants of super-transus solution treatment (ST). The objective was to obtain a low Young’s modulus with sufficient high strength in purpose to use the alloy as a biomaterial for orthopedic implants. The microstructure analysis was conducted through X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) investigations. The analyzed mechanical properties reveal promising values for yield strength (YS) and ultimate tensile strength (UTS) of about 770 and 1100 MPa, respectively, with a low value of Young’s modulus of about 48–49 GPa. The conclusion is that satisfactory mechanical properties for this type of alloy can be obtained if considering a proper combination of SPD + ST parameters and a suitable content of β-stabilizing alloying elements, especially the Zr/Nb ratio.

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The ω phase transformation during the low temperature aging and low rate heating process of metastable β titanium alloys

Cited by 27 publications

References 35 publications

Microstructure and Mechanical Properties Evolution during Solution and Ageing Treatment for a Hot Deformed, above β-transus, Ti-6246 Alloy

Microstructure and Mechanical Properties Evolution during Solution and Ageing Treatment for a Hot Deformed, above β-transus, Ti-6246 Alloy

Titanium alloys developed on the basis of the addition of cheap strong eutectoid β-stabilisers

Tailoring a Low Young Modulus for a Beta Titanium Alloy by Combining Severe Plastic Deformation with Solution Treatment

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