Monitoring residual strain relaxation and preferred grain orientation of additively manufactured Inconel 625 by in-situ neutron imaging

Tremsin, Anton S.; Gao, Yan; Makinde, A.; Bilheux, Hassina Z.; Bilheux, J.‐C.; An, Ke; Shinohara, T.; Oikawa, Kenichi

doi:10.1016/j.addma.2021.102130

Cited by 11 publications

(4 citation statements)

References 73 publications

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“…Numerous studies have explored the formation of residual stresses in materials produced through PBF-LB/M manufacturing. These studies examine the impact on the material of various factors, including process parameters [13,14]-with a specific focus on scanning strategies [5,7,[15][16][17]-as well as material properties, heat treatments [11,15,18], and the geometry of additively manufactured parts (AMed) [5]. Other studies have approached this topic by considering a combination of factors.…”

Section: Introductionmentioning

confidence: 99%

“…The primary and widely adopted approach to reduce residual stresses in AM parts, performed before detaching them from the baseplate, involves stress relief heat treat-ment [11,18,19]. Other stress reduction techniques used by various authors considered the preheating the chamber and build plate [5,7,9], decreasing the energy density [6,11,16,17] or changing the scan vector length [5,20].…”

Section: Introductionmentioning

confidence: 99%

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Assessment of Residual Stresses in Laser Powder Bed Fusion Manufactured IN 625

Paraschiv,

Matache,

Vladut

2024

Materials

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Residual stresses pose significant challenges in the powder bed fusion of metals using a laser (PBF-LB/M), impacting both the dimensional accuracy and mechanical properties. This study quantitatively analyzes deformation and residual stresses in additively manufactured Inconel 625. Investigating both as-built and stress-relieved states with varied scanning strategies (90°, 67°, strip, and 90° chessboard) in PBF-LB/M/IN625, distortion is evaluated using the bridge curvature method. Quantitative measurements are obtained through 3D laser surface scanning on pairs of bridge specimens—one measured before and after detachment from the build plate, and the other undergoing stress-relieving heat treatment at 870 °C for 1 h. The findings reveal that, among as-built specimens, the 90° and 90° strip strategies induce the least distortion, followed by the 67° and chessboard 90° strategies. Furthermore, stress-relief treatment significantly reduces residual stress levels. After post-treatment, the deformation in X-axis samples with 90° and 90° strip strategies decreases by 39% and 42%. In contrast, the samples with the 67° and 90° checkerboard strategies exhibit more pronounced reductions of 44% and 63%, respectively. These quantitative results contribute useful insights for optimizing PBF-LB/M/IN625 processes in additive manufacturing.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Assessment of Residual Stresses in Laser Powder Bed Fusion Manufactured IN 625

Paraschiv,

Matache,

Vladut

2024

Materials

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“…This method can be extended to multiple detector banks to compute strain in multiple strain directions. Neutron diffraction-based strain mapping (NDSM) has been used for several applications such as evaluating strains in additively manufactured (AM) parts [4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Adaptive sampling for accelerating neutron diffraction-based strain mapping ^*

Venkatakrishnan

Fancher

Ziatdinov³

et al. 2023

Mach. Learn.: Sci. Technol.

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Neutron diffraction is a useful technique for mapping residual strains in dense metal objects. The technique works by placing an object in the path of a neutron beam, measuring the diffracted signals and inferring the local lattice strain values from the measurement. In order to map the strains across the entire object, the object is stepped one position at a time in the path of the neutron beam, typically in raster order, and at each position a strain value is estimated. Typical dwell times at neutron diffraction instruments result in an overall measurement that can take several hours to map an object that is several tens of centimeters in each dimension at a resolution of a few millimeters, during which the end users do not have an estimate of the global strain features and are at risk of incomplete information in case of instruments outages. In this paper, we propose an object adaptive sampling strategy to measure the significant points first. We start with a small initial uniform set of measurement points across the object to be mapped, compute the strain in those positions and use a machine learning technique to predict the next position to measure in the object. Specifically,we use a Bayesian optimization based on a Gaussian process regression method to infer the underlying strain field from a sparse set of measurements and predict the next most informative positions to measure based on estimates of the mean and variance in the strain fields estimated from the previously measured points. We demonstrate our real-time measure-infer-predict workflow on additively manufactured steel parts- demonstrating that we can get an accurate strain estimate even with 30-40% of the typical number of measurements - leading the path to faster strain mapping with useful real-time feedback. We emphasize that the proposed method is general and can be used for fast mapping of other material properties such as phase fractions from time-consuming point-wise neutron measurements.

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“…Researchers often only consider the effect of residual stresses at the part scale. Different approaches have been developed to simulate the residual stress at the part-scale level (Gouge et al, 2019;Setien et al, 2019;Tremsin et al, 2021). The inherent strain method induces strain in a small region of a part and applies it to the entire part to exclude the thermal simulation (Huang et al, 2016;Bugatti and Semeraro 2018;Chen et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

An Efficient Track-Scale Model for Laser Powder Bed Fusion Additive Manufacturing: Part 2—Mechanical Model

et al. 2021

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This is the second of two manuscripts that presents a computationally efficient full-field deterministic model for laser powder bed fusion (LPBF). The Hybrid Line (HL) thermal model developed in part I is extended to predict the in-process residual stresses due to laser processing of a nickel-based superalloy, RENÉ 65. The computational efficiency and accuracy of the HL thermo-mechanical model is first compared to the exponential decaying heat input model on a single-track simulation. LPBF thin-wall builds with three different laser powers and four printing patterns are evaluated in this study and compared with part-scale simulations. The simulations show good agreements with the experimental X-Ray diffraction measured residual stresses. Compared to the laser power, the scanning pattern is demonstrated to have significant effects on residual stresses. Laser scan patterns utilizing short laser paths generate lower tensile stress along the longitudinal direction of the part and higher compressive stress along the build direction.

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Monitoring residual strain relaxation and preferred grain orientation of additively manufactured Inconel 625 by in-situ neutron imaging

Cited by 11 publications

References 73 publications

Assessment of Residual Stresses in Laser Powder Bed Fusion Manufactured IN 625

Assessment of Residual Stresses in Laser Powder Bed Fusion Manufactured IN 625

Adaptive sampling for accelerating neutron diffraction-based strain mapping ^*

An Efficient Track-Scale Model for Laser Powder Bed Fusion Additive Manufacturing: Part 2—Mechanical Model

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Monitoring residual strain relaxation and preferred grain orientation of additively manufactured Inconel 625 by in-situ neutron imaging

Cited by 11 publications

References 73 publications

Assessment of Residual Stresses in Laser Powder Bed Fusion Manufactured IN 625

Assessment of Residual Stresses in Laser Powder Bed Fusion Manufactured IN 625

Adaptive sampling for accelerating neutron diffraction-based strain mapping *

An Efficient Track-Scale Model for Laser Powder Bed Fusion Additive Manufacturing: Part 2—Mechanical Model

Contact Info

Product

Resources

About

Adaptive sampling for accelerating neutron diffraction-based strain mapping ^*