Understanding processing parameters affecting residual stress in selective laser melting of Inconel 718 through numerical modeling

2019 ◽  
Vol 34 (08) ◽  
pp. 1395-1404 ◽  
Author(s):  
Jia Song ◽  
Liang Zhang ◽  
Wenheng Wu ◽  
Beibei He ◽  
Xiaoqing Ni ◽  
...  
Keyword(s):  
Residual Stress ◽  
Numerical Modeling ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Processing Parameters ◽  
Laser Melting ◽  
Image Position

Abstract

Correlation Between Microstructure and Tensile Properties of STS 316L and Inconel 718 Fabricated by Selective Laser Melting (SLM)

2020 ◽  
Vol 20 (11) ◽  
pp. 6807-6814
Author(s):  
Jungsub Lee ◽  
Minshik Lee ◽  
Im Doo Jung ◽  
Jungho Choe ◽  
Ji-Hun Yu ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Tensile Properties ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Tensile Elongation ◽  
Processing Condition ◽  
Processing Parameters ◽  
Fusion Pore ◽  
Laser Melting ◽  
Track Width

The correlation between microstructure and tensile properties of selective laser melting (SLM) processed STS 316L and Inconel 718 were investigated at various heights (top, middle and bottom) and planes (YZ, ZX and XY). Columnar grains and dendrites were formed by directional growth during solidification. The average melt pool width and depth, and scan track width were similar in both specimens due to fixed processing parameters. SLM Inconel 718 has moderate tensile strength (1165 MPa) and tensile elongation (11.5%), whereas SLM STS 316L has outstanding tensile strength (656 MPa) and tensile elongation (75%) compared to other SLM processed STS 316L. Fine columnar diameter (0.5 μm) and dense microstructures (porosity: 0.35%) in SLM STS 316L promoted the enhancement of tensile elongation by suitable processing condition. Fractographic analysis suggested that the lack of fusion pore with unmelted powder should be avoided to increase tensile properties by controlling processing parameters.

Determination of residual stress for Inconel 718 samples fabricated through different scanning strategies in selective laser melting

2020 ◽  
Author(s):  
Vignesh Ram Kumar Rajendran ◽  
Kiriti Mamidi ◽  
Bharath Ravichander ◽  
Behzad Farhang ◽  
Amirhesam Amerinatanzi ◽  
...  
Keyword(s):  
Residual Stress ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Laser Melting ◽  
Scanning Strategies

A Method to Estimate Residual Stress in Metal Parts Made by Selective Laser Melting

2015 ◽  
Author(s):  
Xiaoqing Wang ◽  
Y. Kevin Chou
Keyword(s):  
Residual Stress ◽  
Additive Manufacturing ◽  
Residual Stresses ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Plane Surface ◽  
Texture Evolution ◽  
Large Temperature ◽  
Indentation Hardness ◽  
Laser Melting

Accurate evaluation of residual stresses in structures is very important because they play a crucial role in the mechanical performance of the components. As residual stresses can be introduced into mechanical components during various thermal or mechanical processes such as heat treatment, forming, welding and additive manufacturing. As an additive manufacturing method, selective laser melting (SLM) has become a powerful tool for the direct manufacturing of three dimensional nano-composite components with complex configurations directly from powders using 3D CAD data as a digital information source and energy in the form of a high-power laser beam. Therefore, the application of the SLM technology is necessary to manufacture Inconel 718 superalloy, which has been widely employed in industrial applications due to its remarkable properties. Hence, it is critical to measure and reduce the residual stress in the Inconel 718 parts formed by SLM due to rapid cooling and reheating. In this study, the process-induced residual stress in Inconel 718 parts produced by selective laser melting (SLM) has been investigated using the model established by Carlsson et al., which is an instrumented indentation technique based on the experimental correlation between the indentation characteristic and the residual stress. The samples were sectioned from an Inconel 718 block along its build direction, and subsequently prepared with general metallographic methods for Vickers indentation and measurements by optical microscopy. The residual stress on the scanning surface (Z-plane) and side surface (X-plane) at different build heights have been evaluated in micro-scale with the contact area, indentation hardness and the equai-biaxial residual stress and strain fields. The results show that the residual stress is unevenly distributed in the SLMed parts with some areas have an maximum absolute value around 350 MPa, about 30 percent of the yield strength of Inconel 718. The average residual stresses in the Z-plane and X-plane samples are tensile and compressive, respectively. Besides, the residual stress does not change significantly along the building direction of the part. Moreover, the Vickers hardness of the parts built with the SLM process is comparable to the literature, and the X-plane surface has a higher hardness than the Z-plane surface. The microstructures and texture evolution of the SLM processed Inconel 718 alloy are also investigated. The X-plane shows the columnar structure due to the large temperature gradient while the Z-plane presents the equiaxed structures. The random texture is shown in the SLM processed specimens.

scholarly journals The effect of texture on the low cycle fatigue property of Inconel 718 by selective laser melting

2018 ◽  
Vol 165 ◽  
pp. 02007 ◽  
Author(s):  
Zhongjiao Zhou ◽  
Xu Hua ◽  
Changpeng Li ◽  
Guofeng Chen
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Low Cycle Fatigue ◽  
Added Value ◽  
Cycle Fatigue ◽  
Laser Melting ◽  
Safety Critical ◽  
The Impact

In recent decades, additive manufacturing (AM) technology has shown its great advantages to produce end-use products with complex design and high-added value. However, the AM-specific characters, such as inherent material anomalies (porosity, lack of fusion defects, or inclusions), anisotropy, location-specific properties and residual stresses, prevent AM from widely adoption in safety-critical parts. Therefore, the damage tolerance assessment of AM parts is desperately necessary. In this study, the impact of residual stress and the induced texture (columnar/equiax grain structure) after different heat treatment on the low cycle fatigue (LCF) behavior of Inconel 718 fabricated through selective laser melting (SLM) is investigated. The results showed that the texture of AMed parts can be controlled by suitable heat treatment, based on the residual stress during AM processing acting as the drive force to recrystallization. For SLMed Inconel 718 samples with columnar grains, anisotropic LCF properties exist, while no obvious sensitivity to orientations is shown for samples with equiaxed grains. This work is significantly meaningful to speed up the design-to-product transformation of safety-critical AM parts and optimize the orientation of components for various applications.

Selective laser melting of TiC/H13 steel bulk-form nanocomposites with variations in processing parameters

2017 ◽  
Vol 7 (1) ◽  
pp. 84-89 ◽  
Author(s):  
Bandar AlMangour ◽  
Franklin Yu ◽  
Jenn-Ming Yang ◽  
Dariusz Grzesiak
Keyword(s):  
Selective Laser Melting ◽  
Processing Parameters ◽  
Laser Melting ◽  
H13 Steel ◽  
Image Position

Abstract

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