Microstructure and Tensile Properties of SLM Graphene Reinforced Inconel 718 Alloy After Post Heat Treatment

2018 ◽  
Author(s):  
Yachao Wang ◽  
Jing Shi
Keyword(s):  
Heat Treatment ◽  
Inconel 718 ◽  
Metal Matrix ◽  
High Strength ◽  
Solution Temperature ◽  
Strengthening Effect ◽  
Post Heat Treatment ◽  
Inconel 718 Alloy ◽  
Dense Microstructure ◽  
High Flexibility

Graphene is an ideal reinforcement material for metal matrix composites (MMC) owing to its high strength, high ductility, light weight, as well as good bonding with metal matrix. Additive manufacturing such as selective laser melting (SLM) brings the advantages of low material waste, high flexibility, and short production lead cycle. In this study, graphene nano-platelets (GNPs) reinforced Inconel 718 composites are fabricated by SLM technique and processed under various post heat treatment schemes. It is found that fabrication of GNPs reinforced MMC using SLM technique is a viable approach. The obtained composite possesses dense microstructure and enhanced tensile strength. Post heat treatments at two levels of solution temperature (980 and 1220°C) for 1 hour followed by two-step aging are carried out. The experiment results indicate that addition of GNPs into Inconel 718 matrix results in significant strength improvement. At as-built condition, the ultimate tensile strengths are 997 and 1447 MPa, respectively at 0 and 4.4vol.% GNP content. Moreover, under as-built and solution treated condition, high content of GNPs results in overall higher UTS value and the strengthening effect is most significant at as-built condition. Meanwhile, γ′ and γ″ precipitation hardening is suppressed in the GNPs reinforced composite under aged condition due to the formation of MC carbide and depletion of Nb. Incorporating GNPs in Inconel 718 effectively inhibits the grain growth during post heat treatment.

Microstructure and Tensile Performance of Graphene-Reinforced Inconel 718 Alloy Via Selective Laser Melting and Post-Treatments

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Yachao Wang ◽  
Jing Shi
Keyword(s):  
Selective Laser Melting ◽  
Inconel 718 ◽  
Metal Matrix ◽  
Load Transfer ◽  
High Strength ◽  
Solution Temperature ◽  
Strengthening Effect ◽  
Laser Melting ◽  
Inconel 718 Alloy ◽  
Dense Microstructure

Abstract Graphene is an ideal reinforcement material for metal matrix composites (MMCs) owing to its high strength, high ductility, light weight, as well as good bonding with metal matrix. In this study, graphene nanoplatelets (GNPs) reinforced Inconel 718 composites are fabricated by selective laser melting (SLM) technique and processed under various postheat treatment schemes. It is found that the fabrication of GNPs-reinforced MMC using the SLM technique is a viable approach. The obtained composite possesses dense microstructure and enhanced tensile strength. Postheat treatments at two levels of solution temperature (980 and 1220 °C) for 1 h followed by two-step aging are carried out. The experimental results indicate that the addition of GNPs into Inconel 718 matrix results in significant strength improvement. Under the as-built condition, the ultimate tensile strengths (UTSs) of SLM Inconel 718 materials are 997 and 1447 MPa, respectively, at 0 and 4.4 vol % GNP content. The strengthening effect of GNPs is most prominent under the as-built condition, and the strength of as-built GNPs-reinforced Inconel 718 is higher than that of unreinforced Inconel 718 under any processing conditions. The formation of γ′ and γ″ precipitates is suppressed in the GNPs-reinforced composite under the aging condition due to the formation of metallic carbide (MC) carbide and the depletion of Nb. GNPs effectively inhibits grain growth during postheat treatment. Quantitative investigation of the various strengthening effects demonstrates that load transfer effect is dominating among all contributors.

Precipitates formation and its impact in friction stir welded and post-heat-treated Inconel 718 alloy

2011 ◽  
Vol 1363 ◽  
Author(s):  
Kuk Hyun Song ◽  
Han Sol Kim ◽  
Won Yong Kim
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Inconel 718 ◽  
Rotation Speed ◽  
Base Material ◽  
Post Heat Treatment ◽  
Inconel 718 Alloy ◽  
Friction Stir ◽  
Heat Treated

ABSTRACTIn order to investigate the formation of precipitates such as MC carbides and intermetallic compounds in the friction stir welded and post-heat-treated Inconel 718 alloy, this work was carried out. Furthermore, the microstructural and mechanical properties of welds and post-heat-treated material were evaluated to identify the effect on precipitates formed during post-heat-treatment. Friction stir welding (FSW) was performed at a rotation speed of 200 rpm and welding speed of 150 mm/min; heat treatment was performed after welding at 720 °C for 8 hours in vacuum. As a result, the grain size due to FSW was notably refined from 5–20 μm in the base material to 1–3 μm in the stir zone; this was accompanied by dynamic recrystallization, which resulted in enhancements in the mechanical properties as compared to the base material. In particular, applying heat treatment after FSW led to improvements in the mechanical properties of the welds—the microhardness and tensile strength increased by more than 50% and 40% in fraction, respectively, as compared to FSW alone.

Effect of Post Heat Treatment on the Microstructure and Tensile Properties of Nano TiC Particulate Reinforced Inconel 718 by Selective Laser Melting

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Yachao Wang ◽  
Jing Shi
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Solution Treatment ◽  
Nano Particles ◽  
Solution Temperature ◽  
Laser Melting ◽  
Post Heat Treatment ◽  
Particulate Reinforced

Abstract To strengthen the metal components by selective laser melting (SLM), adding reinforcement particles and applying post treatments are generally regarded as the two effective means. However, how post heat treatment affects the properties of nano particulate reinforced metal composites obtained by laser additive manufacturing (AM) processes has rarely been studied. In this study, Inconel 718 matrix composite reinforced by 0.5 wt% nano TiC particles was prepared using SLM. To evaluate the effect of the heat treatment routines on the performance of the SLM-produced composite, two levels of solution temperature (980 and 1100 °C) were designed, and the solution treatment was followed by a standard two-step aging (720 °C for 8 h and 620 °C for 8 h). Scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) observations were performed to examine the microstructure, and transmission electron microscopy (TEM) observation was conducted to characterize the morphologies of incorporated nano particles and precipitated phases. Tensile tests were conducted to evaluate the mechanical properties of the formed composites. It was found that nano particles can effectively strengthen the metal matrix under both as-built and heat-treated conditions, and the material undergoes static recrystallization during the post heat treatment. Also, it was discovered that nano TiC particles play an important role in refining the microstructure of Inconel 718 composite below 980 °C. The maximum tensile strength of 1370 MPa was observed under 980 °C + aging condition, representing a 16% increase as compared with the unreinforced Inconel 718.

scholarly journals Analysis of the Part Distortions for Inconel 718 SLM: A Case Study on the NIST Test Artifact

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5087
Author(s):  
Silvia Martínez ◽  
Naiara Ortega ◽  
Diego Celentano ◽  
Antonio J. Sánchez Egea ◽  
Eneko Ukar ◽  
...  
Keyword(s):  
Inconel 718 ◽  
Thermal Gradient ◽  
Thermal Stresses ◽  
Weight Ratio ◽  
Coordinate Measuring Machine ◽  
High Strength ◽  
Inconel 718 Alloy ◽  
Geometrical Distortion ◽  
Measurement Protocol ◽  
Measuring Machine

The present paper evaluates the misalignment and geometry distortion of the standard National Institute of Standards and Technology (NIST) test artifact in Inconel 718 alloy, when several layers with and without supports are employed to manufacture it by the Selective Laser Melting (SLM) process. To this end, a coordinate-measuring machine (CMM) is used to measure the geometrical distortion in each manufacturing configuration, following the same measurement protocol. The results show that the laser path strategy favors a thermal gradient which, consequently, induces geometrical distortions in the part. To prove this hypothesis, a numerical simulation is performed to determine the thermal gradient and the pattern of the residual stresses. It was found that the geometrical distortion certainly depends on the position of the feature position and laser strategy, where thermal cycles and residual thermal stresses had an impact in the end-part geometry, especially if a high strength-to-weight ratio commonly used in aeronautics is present.

Effect of Aging Heat Treatment on the Mechanical Properties in Inconel 718 Alloy

2013 ◽  
Vol 30 (3) ◽  
pp. 271-277 ◽  
Author(s):  
Hee Jae Kang ◽  
Jung Min Kim ◽  
Sung Hwan Jee ◽  
Jie Hyun Sung ◽  
Young Hee Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Inconel 718 ◽  
Inconel 718 Alloy ◽  
Aging Heat Treatment
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