Solidification path of single-crystal nickel-base superalloys with minor carbon additions under laser rapid directional solidification conditions

Yun, Liang; Li, Jia; Liu, An; Pang, Xiaolu; Wang, Huaming

doi:10.1016/j.scriptamat.2016.08.039

Cited by 50 publications

(8 citation statements)

References 33 publications

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“…The measured average primary dendrite arm spacing in cladding layers ranges from 3 to 5 μm, which is about two orders of magnitude smaller than in the substrate (~200 μm) due to the steep temperature gradient and fast cooling rate during the laser 3D printing process, indicating the interdendritic segregation in cladding layers are greatly suppressed [14]. Here, by using SEM and EPMA, the microstructure and element distribution near the root and tip are investigated and demonstrated in Figs.…”

Section: Elemental Distribution Near the Crack Regionmentioning

confidence: 97%

“…However, hot cracks have been observed in the cladding layers, which is one of the greatest concerns for the application of this technique [5]. Due to the high solidification rate and the cyclic thermal loading accompanying the repeated layer-by-layer deposition, 3D printing produces finer dendrite and γ/γ′ networks [10][11][12], higher defect concentration [13], less element segregation [8,14], and different strain/stress distribution [15,16], when compared to conventional casting products. Consequently, accurate measurements of the microscopic strain, elemental segregation, and phase distribution in a laser 3D printed Ni-based superalloy are needed to understand the crack formation mechanism and to optimize the manufacturing parameters.…”

Section: Introductionmentioning

confidence: 99%

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Mechanism of heat affected zone cracking in Ni-based superalloy DZ125L fabricated by laser 3D printing technique

Chen

Tamura

2018

Materials & Design

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• The heat affected zone cracking initiates due to the re-melting of preexisting intergranular γ/γ′ eutectics and coarse γ′.• The transverse tensile strain/stress causing the initiation and propagation of crack is quantitatively measured.• The micro-size MC carbides are considered to be a possible contributor to the hot cracking initiation. Laser 3D printing is a promising technique to repair damaged Ni-based superalloy components. However, the occurrence of heat affected zone (HAZ) cracking severely limits its applicability. Here we unravel the cracking mechanism by studying the element, phase, defect, and strain distribution around an intergranular crack that initiated from the primary HAZ. Using synchrotron X-ray Laue microdiffraction, we measured high tensile strain/ stress transverse to the building direction in both the primary HAZ and the cladding layers, as well as highdensity dislocations, which resulted from the thermal contraction and rapid precipitation of γ′ phase. The crack initiated because the transverse tensile strain/stress tore up the liquid film formed by the low-melting point preexisting phases in the primary HAZ, such as γ/γ′ eutectics and coarse γ′ precipitates. The incoherent carbide particles were frequently observed near the crack root as local strain concentrators. In the cladding layers, micro-segregation could not be completely avoided, thus the hot crack continued to propagate over several layers with the assistance of the transverse tensile stress. Our investigations provide a useful guideline for the optimization of the 3D printing process to repair Ni-based superalloys with high susceptibility to hot cracking.

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Section: Elemental Distribution Near the Crack Regionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Mechanism of heat affected zone cracking in Ni-based superalloy DZ125L fabricated by laser 3D printing technique

Chen

Tamura

2018

Materials & Design

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“…When depositing a new layer, the adjacent as-deposited layer partly re-melts to form a strong metallurgical bond [22]. Due to the high solidification rate and the cyclic thermal loading accompanying the repeated layer deposition, 3D printing produces finer dendrite and γ/γ networks [21], higher microstructural defect concentration [23], less element segregation [24], and different strain/stress distribution [25,26], as compared to conventional casting products. Moreover, it is widely recognized that once the combined amount of Al and Ti exceeds 6 wt %, the alloy becomes extremely susceptible to hot cracking in the heat-affected zone (HAZ).…”

Section: Laser-assisted 3d Printed Ni-based Superalloysmentioning

confidence: 99%

Quantitative Scanning Laue Diffraction Microscopy: Application to the Study of 3D Printed Nickel-Based Superalloys

Zhou

Kou

et al. 2018

QuBS

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Progress in computing speed and algorithm efficiency together with advances in area detector and X-ray optics technologies have transformed the technique of synchrotron radiation-based scanning Laue X-ray microdiffraction. It has now evolved into a near real-time quantitative imaging tool for material structure and deformation at the micrometer and nanometer scales. We will review the achievements of this technique at the Advanced Light Source (Berkeley, CA, USA), and demonstrate its application in the thorough microstructural investigations of laser-assisted 3D printed nickel-based superalloys.

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“…In this condition, the ceramic particles which orig i nal ly uniformly dispersed in the liquid pool cannot ag glom erate in such a short time, thus homogenously distributing in the matrix. Meanwhile, the rapid solidification is able to refine the microstructure, which is also beneficial to enhance the corrosion re sis tance of Mg alloys [15] .…”

Section: Introductionmentioning

confidence: 99%

Mechanism for corrosion protection of β-TCP reinforced ZK60 via laser rapid solidification

Deng

Yang

Gao

et al. 2024

IJB

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It remains the primary issue to enhance the corrosion resistance of Mg alloys for their clinical applications. In this study, β-tricalcium phosphate (β-TCP) was composited with Mg-6Zn-1Zr (ZK60) using laser rapid solidification to improve the degradation behavior. Results revealed rapid solidification effectively restrained the aggregation of β-TCP, which thus homogenously distributed along grain boundaries of α-Mg. Significantly, the uniformly distributed β-TCP in the matrix promoted the formation of apatite layer on the surface, which contributed to the formation of a compact corrosion product layer, hence retarding the further degradation. Furthermore, ZK60/8β-TCP (wt. %) composite showed improved mechanical strength, as well as improved cytocompatibility. It was suggested that laser rapidly solidified ZK60/8β-TCP composite might be a potential materials for tissue engineering.

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Solidification path of single-crystal nickel-base superalloys with minor carbon additions under laser rapid directional solidification conditions

Cited by 50 publications

References 33 publications

Mechanism of heat affected zone cracking in Ni-based superalloy DZ125L fabricated by laser 3D printing technique

Mechanism of heat affected zone cracking in Ni-based superalloy DZ125L fabricated by laser 3D printing technique

Quantitative Scanning Laue Diffraction Microscopy: Application to the Study of 3D Printed Nickel-Based Superalloys

Mechanism for corrosion protection of β-TCP reinforced ZK60 via laser rapid solidification

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