Superplasticity in Ti–6Al–4V: Characterisation, modelling and applications

Alabort, Enrique; Putman, Duncan; Reed, Roger C.

doi:10.1016/j.actamat.2015.04.056

Cited by 214 publications

(103 citation statements)

References 64 publications

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“…5-a). When the sample is deformed on superplastic conditions, we can expect the loss of texture due to the grain boundary sliding deformation mechanism [13][14]. But in Fig.…”

Section: Resultsmentioning

confidence: 99%

Superplasticity in Fine Grain Ti-6Al-4V Alloy: Mechanical Behavior and Microstructural Evolution

Despax

Vidal

Delagnes

et al. 2018

DDF

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Titanium Ti-6Al-4V alloys are known to exhibit interesting superplastic properties for different conditions of temperature and strain rate, depending on the initial grain size. Even if superplasticity is generally explained in terms of grain boundary sliding (GBS) accompanied by several accommodation mechanisms, it appears that the micromechanisms of superplasticity are still controversial especially at the grain scale and even more at lower scale. These micromechanisms, involving microstructural evolution, depend also on the SPF conditions (temperature, strain rate and initial microstructure). In this study, the flow stress in the Ti-6Al-4V alloy is investigated for different strain rate and for temperature in the range of the α/β transformation. The preferred orientation evolution of alpha phase grains for different percentage of deformation is studied for a non-optimal SPF regime (920°C-10-4 s-1) in order to highlight the microstructural evolution and so the deformation mechanisms involved. For that, mechanical interrupted test combined with Scanning Electron Microscopy (SEM) and Electron Back Scatter Diffraction (EBSD) are used.

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“…5-a). When the sample is deformed on superplastic conditions, we can expect the loss of texture due to the grain boundary sliding deformation mechanism [13][14]. But in Fig.…”

Section: Resultsmentioning

confidence: 99%

Superplasticity in Fine Grain Ti-6Al-4V Alloy: Mechanical Behavior and Microstructural Evolution

Despax

Vidal

Delagnes

et al. 2018

DDF

View full text Add to dashboard Cite

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“…They observed a local mass flow around sliding boundaries using FIB-drawn submicron grids and concluded that Spingarn and Nix-type diffusion was the dominant accommodation in region II [7]. Grain growth has been also detected below region II [2,[28][29][30] and the true deformation mechanism needs to facilitate this microstructural evolution. The mechanisms below region II are expected to be revealed using the present two-dimensional analysis in a future publication.…”

Section: Verification Of the Mechanism By Reviewing Past Studiesmentioning

confidence: 99%

“…Recently, Alabort et al [2] have shown that microstructural evolution depended significantly on strain rates in a superplastic titanium alloy. According to their report, grains became finer via dynamic recrystallization at high strain rates but coarser via grain growth at slow rates.…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional grain boundary sliding and mantle dislocation accommodation in ODS ferritic steel

et al. 2016

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The mechanism governing grain boundary sliding (GBS) accommodated by dislocation and microstructural evolution in regions II/III and III was studied to understand superplasticity.Two-dimensional GBS that occurred during high-temperature shear in oxide dispersion strengthened ferritic steel exhibiting an elongated and aligned grain structure was analyzed using surface markers drawn by focused ion beams. In addition, the accommodating dislocation structure was evaluated by electron back-scattered diffraction and electron channeling contrast imaging. In the initial stage of deformation, GBS triggered dislocation slippage in "mantle" areas near grain boundaries. These mantles tended to appear around GBS-resistant areas such as curved boundaries and grain protrusions. Next, the mantle dislocations generated dislocation walls before forming low-angle boundaries (LABs) along {110} crystallographic planes via dynamic recovery at the core/mantle boundaries. Finally, secondary GBS or rigid rotation occurred at the newly formed LABs to compensate for the initial GBS and resulted in continuous dynamic recrystallization. These mantle dislocation activities and substructural evolution mechanisms were graphically modeled and validated by comparison with previous studies. Keywordssuperplasticity, continuous dynamic recrystallization, dynamic recovery, electron back-scattered diffraction (EBSD), electron channeling contrast imaging (ECCI)

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“…Notably, artificial neural networks have been used extensively in determining the mechanical properties and the kinetics of the phase transformation of titanium [7][8][9][10][11][12][13], nickel [14] and steel [15][16][17][18][19][20]. Genetic algorithm has also been used broadly in materials science [21][22][23][24] to optimize parameters involved in a phenomenon [25,26] and also microstructural evolutions [27,28]. In some cases, GA has been integrated with ANN to optimize the results of a developed neural network model [29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Developing a phenomenological equation to predict yield strength from composition and microstructure in β processed Ti-6Al-4V

Ghamarian

Hayes

Samimi

et al. 2016

Materials Science and Engineering: A

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A constituent-based phenomenological equation to predict yield strength values from quantified measurements of the microstructure and composition of β processed Ti-6Al-4V alloy was developed via the integration of artificial neural networks and genetic algorithms. It is shown that the solid solution strengthening contributes the most to the yield strength (~80% of the value), while the intrinsic yield strength of the two phases and microstructure have lower effects (~10% for both terms). Similarities and differences between the proposed equation and the previously established phenomenological equation for the yield strength prediction of the α+β processed Ti-6Al-4V alloys are discussed. While the two equations are very similar in terms of the intrinsic yield strength of the two constituent phases, the solid solution strengthening terms and the 'Hall-Petch'-like effect from the alpha lath, there is a pronounced difference in the role of the basketweave factor in strengthening. Finally, Monte Carlo simulations were applied to the proposed phenomenological equation to determine the effect of measurement uncertainties on the estimated yield strength values. AbstractA constituent-based phenomenological equation to predict yield strength values from quantified measurements of the microstructure and composition of β processed Ti-6Al-4V alloy was developed via the integration of artificial neural networks and genetic algorithms. It is shown that the solid solution strengthening contributes the most to the yield strength (~80% of the value), while the intrinsic yield strength of the two phases and microstructure have lower effects (~10% for both terms). Similarities and differences between the proposed equation and the previously established phenomenological equation for the yield strength prediction of the α+β processed Ti-6Al-4V alloys are discussed. While the two equations are very similar in terms of the intrinsic yield strength of the two constituent phases, the solid solution strengthening terms and the 'Hall-Petch'-like effect from the alpha lath, there is a pronounced difference in the role of the basketweave factor in strengthening. Finally, Monte Carlo simulations were applied to the Final document prior to publication in Materials Science and Engineering A Available at http://dx.doi.org/10:1016/j.msea.2016.02.052proposed phenomenological equation to determine the effect of measurement uncertainties on the estimated yield strength values.

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Superplasticity in Ti–6Al–4V: Characterisation, modelling and applications

Cited by 214 publications

References 64 publications

Superplasticity in Fine Grain Ti-6Al-4V Alloy: Mechanical Behavior and Microstructural Evolution

Superplasticity in Fine Grain Ti-6Al-4V Alloy: Mechanical Behavior and Microstructural Evolution

Two-dimensional grain boundary sliding and mantle dislocation accommodation in ODS ferritic steel

Developing a phenomenological equation to predict yield strength from composition and microstructure in β processed Ti-6Al-4V

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