Varied heat treatments and properties of laser powder bed printed Inconel 718

Jiang, Runbo; Mostafaei, Amir; Pauza, Joseph; Kantzos, Christopher; Rollett, Anthony D.

doi:10.1016/j.msea.2019.03.103

Cited by 109 publications

(25 citation statements)

References 52 publications

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“…It means that the mechanical properties can be influenced. This finding is confirmed in another article [Bean et al, 2019], which describes the influence of the print orientation of tensile samples on the final mechanical properties and surface quality. They identify the influence of the anisotropy of the Inconel 718 and confirm that in the Z printing direction, samples had approximately 35 MPa lower yield and tensile stress.…”

Section: Introductionsupporting

confidence: 60%

Application of Laser Surface Polishing on Additive Manufactured Parts of Inconel 718 Nickel-Based Superalloy

Bureš¹,

Zetek²

2020

MM SJ

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This article deals with the influence of laser polishing parameters on the final surface quality of nickel-based superalloy Inconel 718 produced by metal additive manufacturing. The aim is to optimize the laser polishing process parameters to reduce the surface roughness of the sample. The investigated parameters of the laser are scanning speed, frequency, focal length, and pulsed and continuous wave regimes are considered. The samples of Inconel 718 are produced by direct metal laser sintering technology. Depending on the printing orientation, the roughness after AM is Ra 5 -12 µm. The samples were machined to ensure uniformity of the monitored and tested surface. An IFM -G4 3D optical microscope is used for the surface evaluation. The initial roughness of the samples before applying laser polishing was Ra 1 -2 µm. The roughness after laser polishing is significantly reduced to Ra 0.369 µm.

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Section: Introductionsupporting

confidence: 60%

Application of Laser Surface Polishing on Additive Manufactured Parts of Inconel 718 Nickel-Based Superalloy

Bureš¹,

Zetek²

2020

MM SJ

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“…Furthermore, a weak <100> texture along the build direction existed with an intensity of ∼2.2 MUD (multiples of uniform density). These observations are in agreement with the as-built microstructural features commonly reported for LB-PBF Alloy 718 [ 27 , 28 , 29 ]. In the DA condition, as shown in Figure 5 , the microstructure in terms of the grain morphology and texture was identical to that of the AB condition, which is in agreement with the published literature [ 27 , 28 ].…”

Section: Resultssupporting

confidence: 92%

“…The maximum IPF texture intensity was relatively higher parallel to the build direction than perpendicular to it. Both these facts indicate that the material has undergone recovery and grain growth, and not the commonly reported recrystallization and grain growth [ 28 , 30 ].…”

Section: Resultsmentioning

confidence: 93%

On the Microstructure of Laser Beam Powder Bed Fusion Alloy 718 and Its Influence on the Low Cycle Fatigue Behaviour

et al. 2020

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Additive manufacturing of Alloy 718 has become a popular subject of research in recent years. Understanding the process-microstructure-property relationship of additively manufactured Alloy 718 is crucial for maturing the technology to manufacture critical components. Fatigue behaviour is a key mechanical property that is required in applications such as gas turbines. Therefore, in the present work, low cycle fatigue behaviour of Alloy 718 manufactured by laser beam powder bed fusion process has been investigated. The material was tested in as-built condition as well as after two different thermal post-treatments. Three orientations with respect to the building direction were tested to evaluate the anisotropy. Testing was performed at room temperature under controlled amplitudes of strain. It was found that defects, inclusions, strengthening precipitates, and Young’s modulus influence the fatigue behaviour under strain-controlled conditions. The strengthening precipitates affected the deformation mechanism as well as the cycle-dependent hardening/softening behaviour. The defects and the inclusions had a detrimental effect on fatigue life. The presence of Laves phase in LB-PBF Alloy 718 did not have a detrimental effect on fatigue life. Young’s modulus was anisotropic and it contributed to the anisotropy in strain-life relationship. Pseudo-elastic stress vs. fatigue life approach could be used to handle the modulus-induced anisotropy in the strain-life relationship.

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“…According to Bragg's law, changes in the peak positions (2θ) are explained by variations in lattice spacing, which consequently refer to change in material composition [34]. Also, it is well recognized that the atomic size of Nb, Ti and Mo, which are the dominant segregated elements in the as-printed condition, are 33%, 18% and 27.5% larger than that of Ni, respectively [35].…”

Section: Spectrum Phasementioning

confidence: 99%

“…This indicates that noticeable changes in lattice parameters are expected to occur during the dissolution and/or rejection of these solute elements. Thus, following the changes in the peak positions helps to follow the precipitation/dissolution of Nb, Ti and Mo during the heat-treatments [34]. Figure 12c,d shows the peak position of the γ (111) plane before and after aging treatment.…”

Section: Spectrum Phasementioning

confidence: 99%

Influence of Homogenization and Solution Treatments Time on the Microstructure and Hardness of Inconel 718 Fabricated by Laser Powder Bed Fusion Process

et al. 2020

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In the present study, Inconel 718 (IN718) superalloy fabricated by laser powder bed fusion (LPBF) has been characterized focusing on the effect of both homogenization and solution treatment time on grains structure, crystallographic texture, precipitates formation/dissolution and material hardness. For this purpose, a heat-treatment time window with a wide range of soaking times for both treatments was established aiming to develop the optimal post-treatment conditions for laser powder bed fused IN718. It was found that the as-printed IN718 is characterized by very fine columnar/cellular dendrites with Laves phase precipitating at the grain boundaries as well as inter-dendritic regions, which differs from the microstructure of wrought and cast materials and requires special heat-treatment conditions different from the standard treatments. The results reveal that the relatively short homogenization treatment at 1080 °C for 1 h was not enough to significantly change the as-printed grain structure and completely dissolve the segregates and Laves phase. However, a completely recrystallized IN718 material and more Laves phase dissolution were obtained after homogenization treatment for 4 h. A further increase in time of the homogenization treatment (7 h) resulted in grain growth and coarsening of carbides precipitates. The solution treatment time at 980 °C did not cause noticeable changes in the crystallographic texture and grain structure. Nevertheless, the amount of δ-phase precipitation was significantly affected by the solution treatment time. After applying the heat-treatment time window, the hardness increased by 51–72% of the as-printed condition depending on the treatment time due to the formation of γ′ and γ″ in the γ-matrix. The highest material hardness was obtained after 1 h homogenization, whereas the prolonged time treatments reduced the hardness. This study provides a comprehensive investigation of the post heat-treatments of the laser powder bed fused IN718 that can result in an optimized microstructure and mechanical behavior for particular applications.

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Varied heat treatments and properties of laser powder bed printed Inconel 718

Cited by 109 publications

References 52 publications

Application of Laser Surface Polishing on Additive Manufactured Parts of Inconel 718 Nickel-Based Superalloy

Application of Laser Surface Polishing on Additive Manufactured Parts of Inconel 718 Nickel-Based Superalloy

On the Microstructure of Laser Beam Powder Bed Fusion Alloy 718 and Its Influence on the Low Cycle Fatigue Behaviour

Influence of Homogenization and Solution Treatments Time on the Microstructure and Hardness of Inconel 718 Fabricated by Laser Powder Bed Fusion Process

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