Peritectic titanium alloys for 3D printing

Barriobero-Vila, Pere; Gussone, Joachim; Stark, Andreas; Schell, Norbert; Haubrich, Jan; Requena, Guillermo

doi:10.1038/s41467-018-05819-9

Cited by 193 publications

(77 citation statements)

References 43 publications

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“…LPBF materials are generally highly textured owing to the directional temperature gradient across the deposited layers that induce epitaxial growth along the building direction [27]. However, depending on the part usage, texture can be modified and reduced to some extent by changing scanning strategy [28] or modifying the alloy composition [29]. For the material investigated in the current study a difference in texture between contour region and bulk was observed.…”

Section: Resultsmentioning

confidence: 82%

Exploring the Correlation between Subsurface Residual Stresses and Manufacturing Parameters in Laser Powder Bed Fused Ti-6Al-4V

Mishurova

Artzt

Haubrich

et al. 2019

Metals

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Subsurface residual stresses (RS) were investigated in Ti-6Al-4V cuboid samples by means of X-ray synchrotron diffraction. The samples were manufactured by laser powder bed fusion (LPBF) applying different processing parameters, not commonly considered in open literature, in order to assess their influence on RS state. While investigating the effect of process parameters used for the calculation of volumetric energy density (such as laser velocity, laser power and hatch distance), we observed that an increase of energy density led to a decrease of RS, although not to the same extent for every parameter variation. Additionally, the effect of support structure, sample roughness and LPBF machine effects potentially coming from Ar flow were studied. We observed no influence of support structure on subsurface RS while the orientation with respect to Ar flow showed to have an impact on RS. We conclude recommending monitoring such parameters to improve part reliability and reproducibility.

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Section: Resultsmentioning

confidence: 82%

Exploring the Correlation between Subsurface Residual Stresses and Manufacturing Parameters in Laser Powder Bed Fused Ti-6Al-4V

Mishurova

Artzt

Haubrich

et al. 2019

Metals

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“…Boron (B), [28,29] tungsten (W) [30] , and a number of rare-earth elements (La, Y, etc.) [31][32][33] have been shown to affect the phase transformation and produce a significant constitutional undercooling and an increase in the nuclei population to encourage equiaxed grain formation in Ti and Ti-based alloys. Nevertheless, although B has a large Q, its use as a grain refiner may be limited when its deleterious effect on ductility caused by the precipitation of titanium borides is considered.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Iron in Minimizing the Microstructural Anisotropy of Ti-6Al-4V Produced by Laser Powder-Bed Fusion

Simonelli

McCartney

Barriobero-Vila

et al. 2020

Metall Mater Trans A

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There remains a significant challenge in adapting alloys for metal-based additive manufacturing (AM). Adjusting alloy composition to suit the process, particularly under regimes close to industrial practice, is therefore a potential solution. With the aim of designing new Ti-based alloys of superior mechanical properties for use in laser powder-bed fusion, this research investigates the influence of Fe on the microstructural development of Ti-6Al-4V. The operating mechanisms that govern the relationship between the alloy composition (and Fe in particular) and the grain size are explored using EBSD, TEM, and in situ high-energy synchrotron X-ray diffraction. It was found that Fe additions up to 3 wt pct lead to a progressive refinement of the microstructure. By exploiting the cooling rates of AM and suitable amount of Fe additions, it was possible to obtain microstructures that can be optimized by heat treatment without obvious precipitation of detrimental brittle phases. The resulting microstructure consists of a desirable and well-studied fully laminar a + b structure in refined prior-b grains.

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“…Finally, we mention in passing a tweak to the recovery approach to lower the dislocation density and hence the RX driving force: the substrate can be heated in situ along with the 3D‐printing (using electron beam, laser, or other heating resource) process. This in situ heating has shown its potential in one‐step manufacturing of newly designed/tailored Ti alloy and maraging steel,41,42 which does not require post‐manufacturing HT and thus is expected to be cheaper and faster, although its application for repairing damaged superalloy single crystals has not been reported. Preheating may also lower the temperature for recovery annealing and shorten its duration, depending on the preheating conditions.…”

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confidence: 99%

Rafting‐Enabled Recovery Avoids Recrystallization in 3D‐Printing‐Repaired Single‐Crystal Superalloys

Chen

Huang

et al. 2020

Advanced Materials

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The repair of damaged Ni‐based superalloy single‐crystal turbine blades has been a long‐standing challenge. Additive manufacturing by an electron beam is promising to this end, but there is a formidable obstacle: either the residual stress and γ/γ ′ microstructure in the single‐crystalline fusion zone after e‐beam melting are unacceptable (e.g., prone to cracking), or, after solutionizing heat treatment, recrystallization occurs, bringing forth new grains that degrade the high‐temperature creep properties. Here, a post‐3D printing recovery protocol is designed that eliminates the driving force for recrystallization, namely, the stored energy associated with the high retained dislocation density, prior to standard solution treatment and aging. The post‐electron‐beam‐melting, pre‐solutionizing recovery via sub‐solvus annealing is rendered possible by the rafting (i.e., directional coarsening) of γ ′ particles that facilitates dislocation rearrangement and annihilation. The rafted microstructure is removed in subsequent solution treatment, leaving behind a damage‐free and residual‐stress‐free single crystal with uniform γ ′ precipitates indistinguishable from the rest of the turbine blade. This discovery offers a practical means to keep 3D‐printed single crystals from cracking due to unrelieved residual stress, or stress‐relieved but recrystallizing into a polycrystalline microstructure, paving the way for additive manufacturing to repair, restore, and reshape any superalloy single‐crystal product.

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Peritectic titanium alloys for 3D printing

Cited by 193 publications

References 43 publications

Exploring the Correlation between Subsurface Residual Stresses and Manufacturing Parameters in Laser Powder Bed Fused Ti-6Al-4V

Exploring the Correlation between Subsurface Residual Stresses and Manufacturing Parameters in Laser Powder Bed Fused Ti-6Al-4V

The Influence of Iron in Minimizing the Microstructural Anisotropy of Ti-6Al-4V Produced by Laser Powder-Bed Fusion

Rafting‐Enabled Recovery Avoids Recrystallization in 3D‐Printing‐Repaired Single‐Crystal Superalloys

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