Characterization and thermal analysis of laser metal deposited γ-TiAl thin walls

Mallikarjuna, B.; Bontha, Srikanth; Krishna, Pravin; Balla, Vamsi Krishna

doi:10.1016/j.jmrt.2021.10.133

Cited by 9 publications

(7 citation statements)

References 30 publications

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“…In our experiment, manganese element is provided by tetrahydrate-manganese acetate (Mn(AC) 2 • 4H 2 O). During grinding and drying, Mn(AC) 2 • 4H 2 O is decomposed to produce gas, resulting in a porous structure in the Mn-doped sample [31,32]. Figures 2(d)-( substitutes Co 3+ ion (radius 0.55 Å), both the bond length around Mn 3+ and the adjacent tetrahedron will be affected, as shown in figures 3(a) and (b).…”

Section: Resultsmentioning

confidence: 99%

Jahn–Taller distortion on exchange interactions between cations in Mn _x Cu_1−xCo₂O₄ system

Zhen²,

Shui³

et al. 2022

J. Phys. D: Appl. Phys.

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Pure-phase MnxCu1-xCo2O4 (x=0, 0.25, 0.5, 0.75 and 1) polycrystalline powders were prepared by using a low-temperature solid-phase reaction method. With doping Mn ion into the octahedral sites, the unit cell transforms from cubic phase to tetragonal phase, and the octahedral Co3+ ions move to the tetrahedral sites and become high spin Co2+ ions. When the doped Mn concentration is low, the sample is dominated by antiferromagnetic interactions between tetrahedral Cu2+. As the Mn concentration increases, ferrimagnetic interactions between tetrahedral Co2+ and octahedral Mn3+ can be observed. When the Mn concentration is high enough, due to strong Jahn-Taller distortion, the eg energy level of Mn splits, which weakens the interactions between the tetrahedral and the octahedral cations, and enhances interactions between the octahedral cations. Ferromagnetic interactions between octahedral Mn3+ and antiferromagnetic interactions between octahedral Mn2+ become obvious. The magnetic ordering temperature has been raised from 20 K to 93 K as the Mn concentration increases, and the maximum exchange bias field is observed to be 1.063 kOe.

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Section: Resultsmentioning

confidence: 99%

Jahn–Taller distortion on exchange interactions between cations in Mn _x Cu_1−xCo₂O₄ system

Zhen²,

Shui³

et al. 2022

J. Phys. D: Appl. Phys.

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“…Which shows that the cracks are susceptible to the laser power. In an another paper by the same author [61] have reported the crack-free surfaces and internal zone of the TiAl thin wall samples is reported. The fabrication of near net shape parts in DED required optimum process parameters [76].…”

Section: Directed Energy Deposition For Fabrication Of Titanium Alumi...mentioning

confidence: 94%

“…Because TiAl intermetallic is inherently brittle in nature and difficult to fabricate conventional methods. PBF and DED are under considerations for the fabrication of TiAl components [57,60,61]. With PBF TiAl based low pressure turbine blade and fuel injector of aeroengine successfully fabrication is reported [10,60,62].…”

Section: Directed Energy Deposition For Fabrication Of Titanium Alumi...mentioning

confidence: 99%

“…It was concluded that the developed finite element model is helpful in process parameters optimization for manufacturing and repair applications. However, a few papers reported on numerical modeling of DED of titanium aluminide intermetallic alloy [2,61,118]. Mallikarjuna et al [2] have shown the thermomechanical modeling of the DED of TiAl alloys.…”

Section: Thermomechanical Modelling Of Ded Processmentioning

confidence: 99%

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Reclamation of intermetallic titanium aluminide aero-engine components using directed energy deposition technology

Mallikarjuna

Reutzel

2022

Manufacturing Rev.

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Titanium Aluminide (TiAl) alloys are intermetallics that offer low density, high melting point, good oxidation and corrosion resistance compared to Ni-based superalloys. As a result, these alloys are used in aero-engine parts such as turbine blades, fuel injectors, radial diffusers, divergent flaps, and more. During operation, aero-engine components are subjected to high thermal loading in an oxidizing and corrosive environment, which results in wear and other material damage. Replacement of the entire component may not be desirable due to long lead time and expense. In such cases, repair and refurbishing may be the best option for the reclamation of TiAl parts. Unfortunately, approved repair technology is not currently available for TiAl based components. Additive Manufacturing (AM) based Directed Energy Deposition (DED) may serve as an option to help repair and restore expensive aero-engine parts. In this work, a review of efforts to utilize the DED technique to repair damaged TiAl-based aerospace parts locally is conducted. Replacing the entire TiAl part is not advisable as it is expensive. DED is a promising technique used to produce, repair, rework, and overhaul (MRO) damaged parts. Considering the high-quality standard of the aircraft industry, DED repaired TiAl parts to be certified for their future use in the aircraft is very important. However, there are no standards for the certification of TiAl repaired parts is reported. Case studies reveal that DED is under consideration for repair of TiAl parts. Hybrid technology comprising machining, repair and finishing capability in a single machine is an attractive implementation strategy to improve repair efficacies. The review shows that the investigations into development and applications of DED-based repairing techniques are limited, which suggests that further investigations are very much needed.

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“…However, LPBF parts are also prone to be laden with process-induced defects and limited to widespread application. Arising from the printing process, defects can be classified as lack of fusion, gas-induced pores/voids, hot cracking and discontinuity [5][6][7][8][9], etc. Among many underlying causes, it is identified that unexpected melt pool dynamics is one of the major contributors to process resulted defects [10,11].…”

Section: Introductionmentioning

confidence: 99%

Impact of sulfur content on thermo-capillarity and melt pool dynamics in laser powder bed fusion of 316L powders

Li,

Kan,

Yin

2023

Mater. Res. Express

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A three-dimensional numerical model is developed to investigate the influence of sulfur content on the transitions of thermo-capillarity and flow dynamics during laser powder bed fusion (LPBF) of 316L powders. The impacts of variations in sulfur contents on thermal behaviors involving heat transfer and solidification characteristics, thermo-capillarity transition, as well as the spatial and directional transitions in flow dynamics, are analyzed through mechanistic modeling techniques. It is observed that transient thermal behaviors, including melt pool profile, track morphology, and solidification processes, are significantly influenced by the contained sulfur concentration. High sulfur concentrations tend to result in finer microstructures and equiaxed grains. Through simulations, it is noted that the transition in the sign of temperature coefficient of surface tension (TCST) is more easily observable in low-sulfur level (0.0001%) but disappears as the sulfur concentration is extremely low. With sulfur content increasing, a more homogenized velocity distribution is observed, accompanied with heightened flow complexity denoted by the emergence of additional branch flows and vortices. These findings offer valuable insights into the underlying physics of melt pool dynamics in the LPBF process and present a potential approach for process optimization.

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Characterization and thermal analysis of laser metal deposited γ-TiAl thin walls

Cited by 9 publications

References 30 publications

Jahn–Taller distortion on exchange interactions between cations in Mn _x Cu_1−xCo₂O₄ system

Jahn–Taller distortion on exchange interactions between cations in Mn _x Cu_1−xCo₂O₄ system

Reclamation of intermetallic titanium aluminide aero-engine components using directed energy deposition technology

Impact of sulfur content on thermo-capillarity and melt pool dynamics in laser powder bed fusion of 316L powders

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Characterization and thermal analysis of laser metal deposited γ-TiAl thin walls

Cited by 9 publications

References 30 publications

Jahn–Taller distortion on exchange interactions between cations in Mn x Cu1−x Co2O4 system

Jahn–Taller distortion on exchange interactions between cations in Mn x Cu1−x Co2O4 system

Reclamation of intermetallic titanium aluminide aero-engine components using directed energy deposition technology

Impact of sulfur content on thermo-capillarity and melt pool dynamics in laser powder bed fusion of 316L powders

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Product

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Jahn–Taller distortion on exchange interactions between cations in Mn _x Cu_1−xCo₂O₄ system

Jahn–Taller distortion on exchange interactions between cations in Mn _x Cu_1−xCo₂O₄ system