scholarly journals Constitutive Modelling of Laser Based Powder Bed Fusion Melted Inconel 718 Superalloy over a Wide Range of Strain Rates

2021 ◽  
Author(s):  
Laura Delcuse ◽  
Slim Bahi ◽  
Urvashi Gunputh ◽  
Paul Wood ◽  
Alexis Rusinek
Keyword(s):  
Inconel 718 ◽  
Bulk Material ◽  
Constitutive Modelling ◽  
Material Behavior ◽  
Vertical Position ◽  
Strain Rates ◽  
Powder Bed Fusion ◽  
Compression Tests ◽  
Powder Bed ◽  
The Difference

The aim of this paper is to determine the material parameters of the Inconel 718 manufactured by Laser Powder Bed Fusion, using the Johnson-Cook model. Different compression tests in quasi-static and dynamic domains were performed under various strain rates, in range of 10-3 s-1 to 2500 s-1 at the room temperature. The difference between the two building directions XY and ZX, horizontal and vertical position from the substrate, was investigated to highlight the influence of the process parameter on the bulk material behavior. Finally, the identified parameters were implemented into a numerical model, describing the behavior of auxetic structure under compression test, and validated using experimental data.

scholarly journals Impact of the Loading Conditions and the Building Directions on the Mechanical Behavior of Biomedical β-Titanium Alloy Produced In Situ by Laser-Based Powder Bed Fusion

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 509
Author(s):  
Housseme Ben Boubaker ◽  
Pascal Laheurte ◽  
Gael Le Coz ◽  
Seyyed-Saeid Biriaie ◽  
Paul Didier ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Electron Backscatter Diffraction ◽  
Material Behavior ◽  
Powder Bed Fusion ◽  
Loading Conditions ◽  
Compression Tests ◽  
Powder Bed ◽  
X Ray ◽  
The Impact

In order to simulate micromachining of Ti-Nb medical devices produced in situ by selective laser melting, it is necessary to use constitutive models that allow one to reproduce accurately the material behavior under extreme loading conditions. The identification of these models is often performed using experimental tension or compression data. In this work, compression tests are conducted to investigate the impact of the loading conditions and the laser-based powder bed fusion (LB-PBF) building directions on the mechanical behavior of β-Ti42Nb alloy. Compression tests are performed under two strain rates (1 s−1 and 10 s−1) and four temperatures (298 K, 673 K, 873 K and 1073 K). Two LB-PBF building directions are used for manufacturing the compression specimens. Therefore, different metallographic analyses (i.e., optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), electron backscatter diffraction (EBSD) and X-ray diffraction) have been carried out on the deformed specimens to gain insight into the impact of the loading conditions on microstucture alterations. According to the results, whatever the loading conditions are, specimens manufactured with a building direction of 45∘ exhibit higher flow stress than those produced with a building direction of 90∘, highlighting the anisotropy of the as-LB-PBFed alloy. Additionally, the deformed alloy exhibits at room temperature a yielding strength of 1180 ± 40 MPa and a micro-hardness of 310 ± 7 HV0.1. Experimental observations demonstrated two strain localization modes: a highly deformed region corresponding to the localization of the plastic deformation in the central region of specimens and perpendicular to the compression direction and an adiabatic shear band oriented with an angle of ±45 with respect to same direction.

scholarly journals Effect of Build Orientation on the Microstructure, Mechanical and Corrosion Properties of a Biodegradable High Manganese Steel Processed by Laser Powder Bed Fusion

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 944
Author(s):  
Martin Otto ◽  
Stefan Pilz ◽  
Annett Gebert ◽  
Uta Kühn ◽  
Julia Hufenbach
Keyword(s):  
Electron Backscatter Diffraction ◽  
Longitudinal Axis ◽  
Manganese Steel ◽  
Compressive Yield Strength ◽  
Powder Bed Fusion ◽  
Compression Tests ◽  
Laser Powder Bed Fusion ◽  
Corrosion Properties ◽  
Powder Bed ◽  
Manufacturing Technologies

In the last decade, additive manufacturing technologies like laser powder bed fusion (LPBF) have emerged strongly. However, the process characteristics involving layer-wise build-up of the part and the occurring high, directional thermal gradient result in significant changes of the microstructure and the related properties compared to traditionally fabricated materials. This study presents the influence of the build direction (BD) on the microstructure and resulting properties of a novel austenitic Fe‑30Mn‑1C‑0.02S alloy processed via LPBF. The fabricated samples display a {011} texture in BD which was detected by electron backscatter diffraction. Furthermore, isolated binding defects could be observed between the layers. Quasi-static tensile and compression tests displayed that the yield, ultimate tensile as well as the compressive yield strength are significantly higher for samples which were built with their longitudinal axis perpendicular to BD compared to their parallel counterparts. This was predominantly ascribed to the less severe effects of the sharp-edged binding defects loaded perpendicular to BD. Additionally, a change of the Young’s modulus in dependence of BD could be demonstrated, which is explained by the respective texture. Potentiodynamic polarization tests conducted in a simulated body fluid revealed only slight differences of the corrosion properties in dependence of the build design.

scholarly journals The effect of build direction and geometric optimization in laser powder bed fusion of Inconel 718 structures with internal channels

2021 ◽  
pp. 109858
Author(s):  
Galina Kasperovich ◽  
Ralf Becker ◽  
Katia Artzt ◽  
Pere Barriobero-Vila ◽  
Guillermo Requena ◽  
...  
Keyword(s):  
Inconel 718 ◽  
Geometric Optimization ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed

scholarly journals Optimization of the Post-Process Heat Treatment of Inconel 718 Superalloy Fabricated by Laser Powder Bed Fusion Process

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 144
Author(s):  
Eslam M. Fayed ◽  
Mohammad Saadati ◽  
Davood Shahriari ◽  
Vladimir Brailovski ◽  
Mohammad Jahazi ◽  
...  
Keyword(s):  
Inconel 718 ◽  
Mechanical Performance ◽  
Solution Treatment ◽  
Heat Treatments ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Homogenization Treatment ◽  
Powder Bed ◽  
Post Process ◽  
High Fraction

In the present study, multi-objective optimization is employed to develop the optimum heat treatments that can achieve both high-mechanical performance and non-distinctive crystallographic texture of 3D printed Inconel 718 (IN718) fabricated by laser powder bed fusion (LPBF). Heat treatments including homogenization at different soaking times (2, 2.5, 3, 3.5 and 4 h) at 1080 °C, followed by a 1 h solution treatment at 980 °C and the standard aging have been employed. 2.5 h is found to be the homogenization treatment threshold after which there is a depletion of hardening precipitate constituents (Nb and Ti) from the γ-matrix. However, a significant number of columnar grains with a high fraction (37.8%) of low-angle grain boundaries (LAGBs) have still been retained after the 2.5 h homogenization treatment. After a 4 h homogenization treatment, a fully recrystallized IN718 with a high fraction of annealing twins (87.1%) is obtained. 2.5 and 4 h homogenization treatments result in tensile properties exceeding those of the wrought IN718 at both RT and 650 °C. However, considering the texture requirements, it is found that the 4 h homogenization treatment offers the optimum treatment, which can be used to produce IN718 components offering a balanced combination of high mechanical properties and adequate microstructural isotropy.

scholarly journals Studies of Post-Fabrication Heat Treatment of L-PBF-Inconel 718: Effects of Hold Time on Microstructure, Annealing Twins, and Hardness

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 266
Author(s):  
Wakshum M. Tucho ◽  
Vidar Hansen
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Additive Manufacturing ◽  
Inconel 718 ◽  
Solution Heat Treatment ◽  
Hold Time ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Annealing Twins ◽  
Complete Recrystallization

The widely adopted temperature for solid solution heat treatment (ST) for the conventionally fabricated Inconel 718 is 1100 °C for a hold time of 1 h or less. This ST scheme is, however, not enough to dissolve Laves and annihilate dislocations completely in samples fabricated with Laser metal powder bed fusion (L-PBF) additive manufacturing (AM)-Inconel 718. Despite this, the highest hardness obtained after aging for ST temperatures (970–1250 °C) is at 1100 °C/1 as we have ascertained in our previous studies. The unreleased residual stresses in the retained lattice defects potentially affect other properties of the material. Hence, this work aims to investigate if a longer hold time of ST at 1100 °C will lead to complete recrystallization while maintaining the hardness after aging or not. For this study, L-PBF-Inconel 718 samples were ST at 1100 °C at various hold times (1, 3, 6, 9, 16, or 24 h) and aged to study the effects on microstructure and hardness. In addition, a sample was directly aged to study the effects of bypassing ST. The samples (ST and aged) gain hardness by 43–49%. The high density of annealing twins evolved during 3 h of ST and only slightly varies for longer ST.

On the manufacturability of Inconel 718 thin-walled honeycomb structures by laser powder bed fusion

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
José M. Zea Pérez ◽  
Jorge Corona-Castuera ◽  
Carlos Poblano-Salas ◽  
John Henao ◽  
Arturo Hernández Hernández
Keyword(s):  
Mechanical Properties ◽  
Inconel 718 ◽  
Dimensional Accuracy ◽  
Honeycomb Lattice ◽  
Lattice Structures ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Content Type ◽  
Powder Bed ◽  
Thin Walled

Purpose The purpose of this paper is to study the effects of printing strategies and processing parameters on wall thickness, microhardness and compression strength of Inconel 718 superalloy thin-walled honeycomb lattice structures manufactured by laser powder bed fusion (L-PBF). Design/methodology/approach Two printing contour strategies were applied for producing thin-walled honeycomb lattice structures in which the laser power, contour path, scanning speed and beam offset were systematically modified. The specimens were analyzed by optical microscopy for dimensional accuracy. Vickers hardness and quasi-static uniaxial compression tests were performed on the specimens with the least difference between the design wall thickness and the as built one to evaluate their mechanical properties and compare them with the counterparts obtained by using standard print strategies. Findings The contour printing strategies and process parameters have a significant influence on reducing the fabrication time of thin-walled honeycomb lattice structures (up to 50%) and can lead to improve the manufacturability and dimensional accuracy. Also, an increase in the young modulus up to 0.8 times and improvement in the energy absorption up to 48% with respect to those produced by following a standard strategy was observed. Originality/value This study showed that printing contour strategies can be used for faster fabrication of thin-walled lattice honeycomb structures with similar mechanical properties than those obtained by using a default printing strategy.

Study of High Temperature Properties of AlSi10Mg Alloy Produced by Laser-Based Powder Bed Fusion

2021 ◽  
Vol 1016 ◽  
pp. 1485-1491
Author(s):  
Marialaura Tocci ◽  
Alessandra Varone ◽  
Roberto Montanari ◽  
Annalisa Pola
Keyword(s):  
High Temperature ◽  
Additive Manufacturing ◽  
Test Temperature ◽  
Vertical Direction ◽  
Material Behavior ◽  
High Temperature Strength ◽  
Powder Bed Fusion ◽  
Mechanical Spectroscopy ◽  
Powder Bed ◽  
Good Thermal Stability

Additive manufacturing of Al alloys can represent an interesting solution for high-performance components in various industrial fields, as for instance the automotive and aerospace industry. Often, for these applications, the alloys are required to withstand exposure to high temperatures. Therefore, the investigation of the evolution of material properties with increasing temperature is of utmost importance in order to assess their suitability for this kind of applications. In the present study, tensile properties at high temperature were investigated for an AlSi10Mg alloy. Samples were manufactured by laser-based powder bed fusion in horizontal and vertical direction in order to examine the influence of building direction on material behavior. The samples were tested in as-built condition and after exposure to high temperature. Tensile tests were performed up to 150 °C and the effect of holding time at the test temperature was evaluated. Furthermore, the alloy was characterized by mechanical spectroscopy in order to evaluate the behavior of dynamic modulus with temperature and, thus, to provide a comprehensive characterization of the material behavior. It was found that the peculiar microstructure of the alloy produced by additive manufacturing is responsible for good high-temperature strength of the material up to 150 °C. The material also exhibits a good thermal stability even after holding at test temperature for 10 h.

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