Process-Defect-Structure-Property Correlations During Laser Powder Bed Fusion of Alloy 718: Role of In Situ and Ex Situ Characterizations

Foster, Samuel; Carver, Keith; Dinwiddie, Ralph B.; List, F.A.; Unocic, Kinga A.; Chaudhary, Anil; Babu, S. S.

doi:10.1007/s11661-018-4870-2

Cited by 49 publications

(40 citation statements)

References 54 publications

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“…This map also shows that the increasing of hatch spacing value resulted in a more rough surface due to decreasing overlap between the melted tracks, which agrees with the trend presented by Foster et al [33]. Surface roughness also increases with the laser scan due to the reduction of the molten layer solidification rate.…”

Section: Surface Topologysupporting

confidence: 89%

Effect of SLM Process Parameters on the Quality of Al Alloy Parts; Part I: Powder Characterization, Density, Surface Roughness, and Dimensional Accuracy

Maamoun¹,

Xue²,

Elbestawi³

et al. 2018

Preprint

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Additive manufacturing (AM) of high strength Al alloys promises to enhance the performance of critical components related to various aerospace and automotive applications. The key advantage of AM is its ability to generate lightweight, robust, and complex shapes. However, the characteristics of the as-built parts may represent an obstacle to satisfy the part quality requirements. The current study investigates the influence of selective laser melting (SLM) process parameters on the quality of parts fabricated from different Al alloys. A design of experiment (DOE) is used to analyze relative density, porosity, surface roughness, and dimensional accuracy according to the interaction effect between the SLM process parameters. The results show a range of energy densities and SLM process parameters for the AlSi10Mg and Al6061 alloys needed to achieve “optimum” values for each performance characteristic. A process map is developed for each material by combining the optimized range of SLM process parameters for each characteristic to ensure good quality of the as-built parts. The second part of this study investigates the effect of SLM process parameters on the microstructure and mechanical properties of the same Al alloys. This comprehensive study is also aimed at reducing the amount of post-processing needed.

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Section: Surface Topologysupporting

confidence: 89%

Effect of SLM Process Parameters on the Quality of Al Alloy Parts; Part I: Powder Characterization, Density, Surface Roughness, and Dimensional Accuracy

Maamoun¹,

Xue²,

Elbestawi³

et al. 2018

Preprint

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show abstract

“…However, in rapid solidification processes such as welding, the undercooling can be substantial. In order to justify our assumption of neglected undercooling, we have used a model by Foster et al [9] to compute the undercooling as a function of the solidification velocity for alloy 718 as follows.…”

Section: Undercoolingmentioning

confidence: 99%

“…Rappaz et al [12] extend the KGT model to multicomponent alloys and used it to study the dendrite growth in electron beam welding of a Fe-Ni-Cr alloy. Foster et al [9] used the extended KGT model to compute the undercooling in laser welding of alloy 718. This model with data from Foster et al [9] was used to calculate the undercooling for alloy 718 for solidification velocities in the range 10 −2 ≤ R L ≤ 10 3 mms −1 .…”

Section: Undercoolingmentioning

confidence: 99%

“…Foster et al [9] used the extended KGT model to compute the undercooling in laser welding of alloy 718. This model with data from Foster et al [9] was used to calculate the undercooling for alloy 718 for solidification velocities in the range 10 −2 ≤ R L ≤ 10 3 mms −1 . The model depends on the temperature gradient, which was assumed to vary linearly between 8 × 10 4 and 10 8…”

Section: Undercoolingmentioning

confidence: 99%

“…The initial value of h must be known in order to integrate (9). We assume that h has the same value as the undeformed thickness h 0 when the GBLF is first formed.…”

Section: Initial Conditionmentioning

confidence: 99%

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Modeling and simulation of weld solidification cracking part II

et al. 2019

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Several advanced alloy systems are susceptible to weld solidification cracking. One example is nickel-based superalloys, which are commonly used in critical applications such as aerospace engines and nuclear power plants. Weld solidification cracking is often expensive to repair, and if not repaired, can lead to catastrophic failure. This study, presented in three papers, presents an approach for simulating weld solidification cracking applicable to large-scale components. The results from finite element simulation of welding are post-processed and combined with models of metallurgy, as well as the behavior of the liquid film between the grain boundaries, in order to estimate the risk of crack initiation. The first paper in this study describes the crack criterion for crack initiation in a grain boundary liquid film. The second paper describes the model for computing the pressure and the thickness of the grain boundary liquid film, which are required to evaluate the crack criterion in paper 1. The third and final paper describes the application of the model to Varestraint tests of Alloy 718. The derived model can fairly well predict crack locations, crack orientations, and crack widths for the Varestraint tests. The importance of liquid permeability and strain localization for the predicted crack susceptibility in Varestraint tests is shown.

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Analytical Methods to Understand Deformation Mechanics in Additively Manufactured Metals

Thomas

Heckman

Kramer

et al. 2021

Thermomechanics &Amp; Infrared Imaging, Inverse Problem Methodologies and Mechanics of Additive &Amp; Advanced Manufactured Mat

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Process-Defect-Structure-Property Correlations During Laser Powder Bed Fusion of Alloy 718: Role of In Situ and Ex Situ Characterizations

Cited by 49 publications

References 54 publications

Effect of SLM Process Parameters on the Quality of Al Alloy Parts; Part I: Powder Characterization, Density, Surface Roughness, and Dimensional Accuracy

Effect of SLM Process Parameters on the Quality of Al Alloy Parts; Part I: Powder Characterization, Density, Surface Roughness, and Dimensional Accuracy

Modeling and simulation of weld solidification cracking part II

Analytical Methods to Understand Deformation Mechanics in Additively Manufactured Metals

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