Microstructure of γ-titanium aluminide processed by selective laser melting at elevated temperatures

Gussone, Joachim; Hagedorn, Yves‐Christian; Gherekhloo, Human; Kasperovich, Galina; Merzouk, Tarik; Hausmann, Joachim

doi:10.1016/j.intermet.2015.07.005

Cited by 125 publications

(40 citation statements)

References 24 publications

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“…Different techniques of substrate preheating have been applied to the LPBF technology, namely IR heaters [5][6][7], preheating or remelting strategies through fast scanning of the laser beam [8][9][10], use of a second defocused laser beam [11], substrate resistive heating [12,13] or baseplate induction circuit [4,14,15]. The greater part of industrial SLM systems employs resistive heaters, which typically allow preheating of the baseplate up to 200°C while the most recently developed systems enable to achieve up to 800°C [13].…”

Section: Introductionmentioning

confidence: 99%

“…Although these systems are particularly effective in reducing local stresses near the base plate, they lose their effectiveness when a full-scale component must be manufactured since their area of influence is limited to the lower parts of the build (due to the inherent nature of the process which relies on the lowering of the base plate). A similar preheating concept was developed by Hagedorn et al whom employed a pancake induction heating circuit capable of achieving up to 1000°C [14,15]. IR heaters have been applied for the preheating of the top layer of the powder bed, however these systems are not energetically efficient [5,7].…”

Section: Introductionmentioning

confidence: 99%

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Defect-free laser powder bed fusion of Ti–48Al–2Cr–2Nb with a high temperature inductive preheating system

et al. 2020

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In the industrial panorama, laser powder bed fusion (LPBF) systems enable the near net shaping of metal powders into complex geometries with unique design features. This makes the technology appealing for many industrial applications, which require high performance materials combined with lightweight design, lattice structures and organic forms. However, many of the alloys that would be ideal for the realisation of these functional components are classified as difficult to weld due to their cracking sensitivity. γ-TiAl alloys are currently processed via electron beam melting (EBM) to produce components for energy generation applications. The EBM process provides crack-free processing thanks to the preheating stages between layers, but lacks geometrical precision. The use of LPBF could provide the means for higher precision, and therefore an easier post-processing stage. However, industrial LPBF systems employ resistive heating elements underneath the base plate which do not commonly reach the high temperatures required for the processing of γ-TiAl alloys. Thus, elevated temperature preheating of the build part and control over the cooling rate after the deposition process is concluded are amongst the features which require further investigations. In this work, the design and implementation of a novel inductive high temperature LPBF system to process Ti-48Al-2Cr-2Nb is presented. Specimens were built with preheating at 800°C and the cooling rate at the end of the build was controlled at 5°C min −1 . Crack formation was suppressed and apparent density in excess of 99% was achieved.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Defect-free laser powder bed fusion of Ti–48Al–2Cr–2Nb with a high temperature inductive preheating system

et al. 2020

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“…Recently, γ-TiAl alloys are introduced as low pressure turbine blade material in civil aircraft engines [2] and first research activities were already started to introduce γ-TiAl powders in PM productions techniques [3,4,5]. We characterised the microstructure of different powder particle size fractions of several alloy compositions by advanced microscopy and diffraction methods.…”

Section: Introductionmentioning

confidence: 99%

Microstructure of gas atomised γ-TiAl based alloy powders

et al. 2017

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Due to the rapid development of advanced additive manufacturing production routes in recent years, the demand of high-quality alloy powders is significantly increased. We studied gas-atomised spherical powders of several Nb-bearing γ-TiAl based alloys, Ti-45Al-10Nb and Ti-45Al-5Nb-xC in at.% (x = 0, 0.5, 0.75, and 1), which were produced using the plasma melting induction guided gas atomization (PIGA) technique. The phase constitution of different powder fractions was determined by synchrotron high-energy X-ray diffraction at the HEMS beamline DESY (Germany), as well as by SEM, EDX and EBSD measurements. Due to the high cooling rates in the range of 10 5 K/s, the powder particles mainly consist of hexagonal close packed α-Ti(Al) and body centred cubic β-Ti(Al)-phase. As the cooling rate depends on the particle size, considerable amounts of the β-phase were only found in the small powder fractions (< 45 µm). The total β-phase amount was generally higher in the alloy with a higher Nb content, and also the effect of carbon as a α 2 -stabilizer was observed. Dendritic cauliflower-like structures are more pronounced in bigger powder particles due to the slower solidification and thus a higher Nb depletion in the remaining melt.

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“…[14] Since the parts are made layer-by-layer deposition, directly from a computer-aided design (CAD) file, complex shape components can be easily manufactured in one-step using this AM technology. Majority of the reported literature on the use of AM to process TiAl is limited to powder bed-based AM technologies such as selective laser melting (SLM) [15,16] and electron beam melting (EBM). [17][18][19][20] Within our knowledge, research related to deposition-based AM of TiAl is very limited.…”

Section: Introductionmentioning

confidence: 99%

Additive Manufacturing of γ‐TiAl: Processing, Microstructure, and Properties

et al. 2016

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Additive manufacturing of g-TiAl intermetallic alloy using laser-engineered net shaping (LENS) is reported. The influence of laser power and scan speed on processability, microstructure, tribological, and electrochemical properties is studied. The results demonstrate that near net shape g-TiAl parts can be fabricated using LENS and defect-free parts are obtained with narrow laser energy input range (40-50 J mm À2 ). The high cooling rates result in massive-like g matrix with small amount of g þ a 2 lamellar. Process parameters strongly influence tribological and electrochemical properties of LENS-processed g-TiAl parts in 3.5% NaCl solution. Wear is of abrasive type with no evidence of corrosion on wear tracks.

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Microstructure of γ-titanium aluminide processed by selective laser melting at elevated temperatures

Cited by 125 publications

References 24 publications

Defect-free laser powder bed fusion of Ti–48Al–2Cr–2Nb with a high temperature inductive preheating system

Defect-free laser powder bed fusion of Ti–48Al–2Cr–2Nb with a high temperature inductive preheating system

Microstructure of gas atomised γ-TiAl based alloy powders

Additive Manufacturing of γ‐TiAl: Processing, Microstructure, and Properties

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