In situ correlative observation of humping-induced cracking in directed energy deposition of nickel-based superalloys

Fleming, Tristan G.; Rees, David Tien; Marussi, Sebastian; Connolley, Thomas; Atwood, Robert C.; Jones, Matthew; Fraser, James M.; Leung, Chu Lun Alex; Peter, D. Le

doi:10.1016/j.addma.2023.103579

Cited by 8 publications

(3 citation statements)

References 48 publications

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“…The results showed that this method yielded penetration depth measurements with an average error of less than 5%. Furthermore, based on the theoretical model that keyholes are prone to porosity during intense depth and shape variations [13][14][15], the team used the abrupt changes in OCT keyhole depth data to infer the formation of porosity. Stadter, Christian, et al [16] attempted to leverage machine learning to extract more information about weld quality hidden in OCT keyhole depth signals.…”

Section: Introductionmentioning

confidence: 99%

Global shutter depth profiling of molten pool and keyhole during laser processing using core-array fiber

Ding,

Yao,

Lei

et al. 2024

High-Power Laser Materials Processing: Applications, Diagnostics, and Systems XIII

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Online 3D depth profiling of molten pool/keyhole during laser processing is of great importance to evaluate the metrics of the live process. The indirect methods based on visual image and thermal radiation suffer low correlations with pool/keyhole behavior, thus the accuracy is typically low. Optical coherence tomography (OCT) shoots a light probe coaxially with the processing beam into the pool/keyhole, hence being able to provide a direct depth measurement. When it comes to profiling the depth of an area, a galvanometer is typically used to scan the area of interests. However, the pool/keyhole intrinsically flows in a highly dynamic mode, the mechanical scanned image suffers blurs and deformation, as a rolling-shutter camera suffers when imaging object is moving fast. To address this issue, a global shutter imaging method is proposed to image the pool area synchronously. A low coherent light is split into multiple fibers, which are then bundled into a core-array fiber and guided parallelly into the laser head, resulting a multiple of interfering pairs captured and imaged at the same moment. The theoretical model of this global shutter imaging method was created and analyzed in terms of the image performance and limitations. A two-core fiber global shutter imaging system was built to demonstrate the imaging performance on molten pool/keyhole. It shows a great potential to capture high quality 3D points of keyhole/molten pool for further fine closed loop control.

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Section: Introductionmentioning

confidence: 99%

Global shutter depth profiling of molten pool and keyhole during laser processing using core-array fiber

Ding,

Yao,

Lei

et al. 2024

High-Power Laser Materials Processing: Applications, Diagnostics, and Systems XIII

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“…Once these physics-based factors can be quantified and calculated, they can be correlated with the experimentally measured surface characteristics data to reveal insights into surface quality and ways to improve it. With the progress in non-contact measurements [31][32][33][34][35][36], it is now possible to extract high-quality data on surface quality. Therefore, what is needed and not available is a method to identify, quantify, and calculate the most important physical factors that affect deposit surface quality and establish a correlation between them and the experimentally measured surface characteristics.…”

Section: Introductionmentioning

confidence: 99%

Improving Deposited Surface Quality in Additive Manufacturing Using Structured Light Scanning Characterization and Mechanistic Modeling

Mukherjee,

Shen,

Liao

et al. 2024

JMMP

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The surface quality of parts fabricated using laser-directed energy deposition additive manufacturing significantly affects the fatigue life, corrosion resistance, and performance of the components. Surface quality improvements remain a key challenge in laser-directed energy deposition because of the involvement of multiple simultaneously occurring physical phenomena controlling the surface characteristics. Here, a unique combination of structured light scanning characterization and mechanistic modeling was used to identify three key physical factors that affect surface quality. These factors include a geometric factor, an instability factor, and a disintegration factor, which were calculated using a mechanistic model and correlated with the surface characteristics data obtained from the structured light scanning characterization. It was found that these factors can precisely explain the variations in the average surface roughness. In addition, skewness and kurtosis of the surfaces made by laser-directed energy deposition were found to be significantly better than those observed in traditional manufacturing. Based on the experimental and modeling results, a surface quality process map was constructed that can guide engineers in selecting appropriate sets of process variables to improve deposit surface quality in additive manufacturing.

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“…Therefore, when choosing a detection method, an appropriate method can be selected based on the specific situation to minimize damage to the test components while ensuring detection accuracy. 14,15 Therefore, adopting numerical simulation methods to simulate the welding process can not only comprehensively understand the generation process of welding stress and the magnitude and distribution of residual stresses after welding but also enable targeted control of residual stresses. This can reduce the amount of testing and save costs.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation and experimental study of residual stress in dissimilar aluminum alloy laser composite welding

Chen,

Tang,

Xie

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part L:

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The study combined experimental and numerical simulation methods to investigate the distribution of residual stress in laser composite welding of dissimilar aluminum alloys 6063 and 5083. Using the Simufact Welding simulation software and a combined volume heat source, the distribution patterns of transverse and longitudinal residual stress fields at different welding speeds were analyzed. The blind hole method was used to test the residual stress after welding. The results showed that the use of a combined volume heat source model for heat source calibration yielded ideal results, and the thermal cycle curve was basically consistent with the simulation and experimental results of residual stress. As the welding speed decreased, the longitudinal residual stress of the parent material on both sides significantly decreased, while the transverse residual stress increased. The majority of tensile and compressive stresses on both sides of the 5083 and 6063 aluminum alloys decreased with a decrease in welding speed. The Von Mises equivalent stress indicated that the cooling process is the main stage for residual stress generation. When the welding speed decreased, the peak value of longitudinal residual stress on the 6063 aluminum alloy side decreased from 230 to 90 MPa, while that on the 5083 aluminum alloy side decreased from 304 to 150 MPa. These findings provide an important basis for controlling and reducing the residual stress and deformation of dissimilar aluminum alloy laser arc composite welded components.

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In situ correlative observation of humping-induced cracking in directed energy deposition of nickel-based superalloys

Cited by 8 publications

References 48 publications

Global shutter depth profiling of molten pool and keyhole during laser processing using core-array fiber

Global shutter depth profiling of molten pool and keyhole during laser processing using core-array fiber

Improving Deposited Surface Quality in Additive Manufacturing Using Structured Light Scanning Characterization and Mechanistic Modeling

Numerical simulation and experimental study of residual stress in dissimilar aluminum alloy laser composite welding

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