Parametric Study on Laser Additive Manufacturing and Subsequent Post Processing of Inconel 718 Thin Walled Structures

2017 ◽  
Author(s):  
Arackal Narayanan Jinoop ◽  
Christ Prakash Paul ◽  
Kushvinder Singh Bindra
Keyword(s):  
Heat Treatment ◽  
Additive Manufacturing ◽  
Inconel 718 ◽  
Fibre Laser ◽  
Maximum Height ◽  
Micro Hardness ◽  
Laser Additive Manufacturing ◽  
Minimum Width ◽  
Thin Walled Structures ◽  
Thin Walled

Laser Additive Manufacturing (LAM) is one of the greener routes for fabrication of Inconel 718 (IN718) components. In the present work, Taguchi L9 array based optimization is performed using grey relational analysis to optimize the process parameters for the fabrication of thin walled structures using a 2 kW fibre laser based additive manufacturing system. Within the framework of the experimental conditions of the study, the LAM processing parameters, i.e., laser power, scan speed and powder feed rate, are optimized for minimum width and maximum height. The optimized parameters are used for the deposition of multi-layered walls and it is subjected to heat treatment at 1000 °C for duration of one-hour, followed by water quenching. Comprehensive investigations on microstructural and mechanical behaviour using optical microscopy (OM), X-ray diffraction (XRD) analysis, micro-hardness and automated ball indentation (ABI) are carried out. Microstructure examinations of LAM deposits of IN718 reveal intermixed dendritic and cellular structures. However, homogenization in microstructure is observed through heat treatment resulting in reduced micro-hardness. It is also observed that there is considerable increase in the crystallite size of the deposits after heat treatment. This study opens a new route for fabrication of thin walled structures using LAM with modified properties by erasing the thermal history through heat treatment.

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.

Review on Powder-Bed Laser Additive Manufacturing of Inconel 718 Parts

2015 ◽  
Author(s):  
Xiaoqing Wang ◽  
Xibing Gong ◽  
Kevin Chou
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Literature Review ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Manufacturing Processes ◽  
Laser Melting ◽  
Laser Additive Manufacturing ◽  
Powder Bed ◽  
General Aspects

This study presents a thorough literature review on the powder-bed laser additive manufacturing processes such as selective laser melting (SLM) of Inconel 718 parts. The paper first introduces the general aspects of powder-bed laser additive manufacturing and then discusses the unique characteristics and advantages of SLM. Moreover, the bulk of this study includes extensive discussions of microstructures and mechanical properties, together with the application ranges, of Inconel 718 parts fabricated by SLM.

The microstructure and mechanical properties of deposited-IN625 by laser additive manufacturing

2017 ◽  
Vol 23 (6) ◽  
pp. 1119-1129 ◽  
Author(s):  
Lanlan Qin ◽  
Changjun Chen ◽  
Min Zhang ◽  
Kai Yan ◽  
Guangping Cheng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Thermal Stability ◽  
Additive Manufacturing ◽  
Dendritic Morphology ◽  
Laves Phase ◽  
Micro Hardness ◽  
Laser Additive Manufacturing ◽  
Content Type ◽  
Annealing Temperatures

Purpose Laser additive manufacturing (LAM) technology based on powder bed has been used to manufacture complex geometrical components. In this study, IN625 superalloys were fabricated by high-power fiber laser without cracks, bounding errors or porosity. Meanwhile, the objectives of this paper are to systemically investigate the microstructures, micro-hardness and the precipitated Laves phase of deposited-IN625 under different annealing temperatures. Design/methodology/approach The effects of annealing temperatures on the microstructure, micro-hardness and the precipitated Laves phase were studied by optical microscope (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS), selected area electron diffraction (SAED), backscattered electron (BSE) imaging in the SEM and transmission electron microscopy (TEM), respectively. The thermal stability of the dendritic morphology about IN625 superalloys was investigated through annealing at temperatures range from 1,000°C to 1,200°C. Findings It is found that the microstructure of deposited-IN625 was typical dendrite structure. Besides, some Laves phase precipitated in the interdendritic region results in the segregation of niobium and molybdenum. The thermal stability indicate that the morphology of dendrite can be stable up to 1,000°C. With the annealing temperatures increasing from 1,000 to 1,200°C, the Laves phase partially dissolves into the γ-Ni matrix, and the morphology of the remaining Laves phase is changing from irregular shape to rod-like or block-like shape. Research limitations/implications The heat treatment used on the IN625 superalloys is helpful for knowing the evolution of microstructures and precipitated phases thermal stability and mechanical properties. Practical implications Due to the different kinds of application conditions, the original microstructure of the IN625 superalloys fabricated by LAM may not be ideal. So exploring the influence of annealing treatment on IN625 superalloys can bring theory basis and guidance for actual production. Originality/value This study continues valuing the fabrication of IN625 by LAM. It shows the effect of annealing temperatures on the shape, size and distribution of Laves phase and the microstructures of deposited-IN625 superalloys.

Characterization of heat affected zone liquation cracking in laser additive manufacturing of Inconel 718

2016 ◽  
Vol 90 ◽  
pp. 586-594 ◽  
Author(s):  
Yuan Chen ◽  
Ke Zhang ◽  
Jian Huang ◽  
Seyed Reza Elmi Hosseini ◽  
Zhuguo Li
Keyword(s):  
Additive Manufacturing ◽  
Heat Affected Zone ◽  
Inconel 718 ◽  
Laser Additive Manufacturing ◽  
Liquation Cracking ◽  
Zone Liquation

Steering column support topology optimization including lattice structure for metal additive manufacturing

2020 ◽  
pp. 095440622094712
Author(s):  
S Mantovani ◽  
GA Campo ◽  
M Giacalone
Keyword(s):  
Additive Manufacturing ◽  
Bulk Material ◽  
Optimization Methods ◽  
Functionally Graded ◽  
Lattice Structures ◽  
Advantages And Disadvantages ◽  
Thin Walled Structures ◽  
Wide Range ◽  
Thin Walled ◽  
Graded Lattice

Structural engineering in the automotive industry has moved towards weight reduction and passive safety whilst maintaining a good structural performance. The development of Additive Manufacturing (AM) technologies has boosted design freedom, leading to a wide range of geometries and integrating functionally-graded lattice structures. This paper presents three AM-oriented numerical optimization methods, aimed at optimizing components made of: i) bulk material, ii) a combination of bulk material and graded lattice structures; iii) an integration of solid, lattice and thin-walled structures. The optimization methods were validated by considering the steering column support of a mid-rear engine sports car, involving complex loading conditions and shape. The results of the three methods are compared, and the advantages and disadvantages of the solutions are discussed. The integration between solid, lattice thin-walled structures produced the best results, with a mass reduction of 49.7% with respect to the existing component.

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