scholarly journals The effects of graphene content on the mechanical properties and thermal conductivity of Inconel 718 superalloy brazed using BNi-2/graphene composite filler metal

2020 ◽  
Vol 16 ◽  
pp. 102828 ◽  
Author(s):  
I.-Kon Lee ◽  
Hung-Hua Sheu ◽  
Heng-Yao Hsu
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Inconel 718 ◽  
Filler Metal ◽  
Graphene Composite ◽  
Inconel 718 Superalloy ◽  
Graphene Content ◽  
Composite Filler

scholarly journals The δ Phase Precipitation of an Inconel 718 Superalloy Fabricated by Electromagnetic Stirring Assisted Laser Solid Forming

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2604 ◽  
Author(s):  
Lyu ◽  
Liu ◽  
Hu ◽  
Yang ◽  
Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electromagnetic Field ◽  
Field Intensity ◽  
Inconel 718 ◽  
Phase Changes ◽  
Electromagnetic Stirring ◽  
The Core ◽  
Laser Solid Forming ◽  
Δ Phase ◽  
Inconel 718 Superalloy

Fabricating an Inconel 718 superalloy using electromagnetic stirring assisted laser solid forming (EMS-LSF) is a novel method to modify its microstructure and mechanical properties by consuming the Nb element in the γ phase to alleviate interdendritic segregation. The precipitate of the δ phase at 950 °C after EMS-LSF can help to achieve the uniform diffusion of Nb, and can also improve its mechanical properties. The precipitation behavior of the δ phase in an EMS-LSF Inconel 718 superalloy with different heat treatment processes has been investigated. The results show that the morphology of the δ phase changes from rod-like to a long-needle shape and tends to grow from the inter dendrite to the core dendrite with electromagnetic field intensity increasing, which is accompanied by the “cutting” and “dissolution” of the Laves phase. Through precipitation kinetics analysis, the precipitation rate of the δ phase is seen to increase with the electromagnetic field intensity increasing. Under a combination of electromagnetic stirring and laser solid forming, the microhardness of the Inconel 718 samples increased slightly due to the fact that a higher content of Nb was distributed in the core dendrite resulting from the serious convection of liquid metal, which can strengthen the matrix.

On Mechanical and Thermal Properties of Epoxy/Graphene Nanocomposites

2018 ◽  
Vol 22 ◽  
pp. 23-33 ◽  
Author(s):  
Seenaa I. Hussein
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Impact Strength ◽  
Mechanical And Thermal Properties ◽  
Graphene Nanocomposites ◽  
Graphene Composite ◽  
Efficiency Increase ◽  
Graphene Content ◽  
The Impact ◽  
Thermal Stability Of

In this research, we have prepared epoxy/graphene nanocomposites (graphene content: 1, 3, 5, 7, and 9 wt%) to investigate some mechanical (impact strength, hardness, and Brazilian tests) and thermal properties (thermal conductivity and thermogravimetric analysis). Our results show that the impact strength, hardness, and compression strength values increased to 5.04 kJ/m2, 79.8, and 27.85 MPa, respectively, as increasing graphene content up to 5 wt% and then decreased for further increasing of the graphene content. The observed reduction in the hardness could be attributed to the samples brittleness. On the other hand, the thermal conductivity increased with increasing the graphene content because of the high thermal conductivity of graphene and thus the efficiency increase with increasing of graphene content. In addition, the thermal stability of epoxy/graphene composite increase compared with pure epoxy resin, while the activation energy for samples consists of 9 wt% graphene greater than those containing 1 wt% graphene.

Characterization of Precipitation Kinetics of Inconel 718 Superalloy by the Stress Relaxation Technique

2012 ◽  
Vol 706-709 ◽  
pp. 2393-2399 ◽  
Author(s):  
Jessica Calvo ◽  
She Yu Shu ◽  
Jose María Cabrera
Keyword(s):  
Mechanical Properties ◽  
Stress Relaxation ◽  
Inconel 718 ◽  
Relaxation Times ◽  
Precipitation Kinetics ◽  
Nickel Chromium ◽  
Phase Intermetallic ◽  
Δ Phase ◽  
Inconel 718 Superalloy

Inconel 718 is a nickel-chromium-iron superalloy which presents excellent mechanical properties at high temperatures, as well as good corrosion resistance and weldability. These characteristics can be optimized with an appropriate control of microstructural features such as grain size and precipitation. Precipitates of different nature can form in these alloys, i.e. γ’’ (a metastable metallic compound Ni3Nb), γ’ (Ni3(Ti, Al), carbides and/or δ phase (intermetallic Ni3Nb). Aging treatments are usually designed to obtain the precipitation required in order to optimize mechanical properties. However, precipitation can also appear induced by deformation and therefore interfere with hot forming operations, such as forging. Under these conditions, precipitation may lead to an increase of the loads required to carry out the process. The aim of the work was the characterization of precipitation kinetics for Inconel 718. With this purpose, stress relaxation tests were carried out at temperatures ranging from 950°C to 800°C. Moreover, different amounts of deformation were applied to the samples, prior to stress relaxation, to evaluate the effect of this variable on inducing precipitation. Some samples were quenched at different relaxation times for metallographic evaluation. The results obtained through mechanical testing, together with a proper characterization of precipitation by Scanning Electron Microscopy, were the basis for obtaining precipitation-time-temperature (PTT) diagrams after different deformation conditions.

Machining Performance Characteristics of Inconel 718 Superalloy Due to Hole-Sinking Ultrasonic Assisted Micro-EDM

2018 ◽  
Vol 17 (01) ◽  
pp. 89-105 ◽  
Author(s):  
Param Singh ◽  
Vinod Yadava ◽  
Audhesh Narayan
Keyword(s):  
Thermal Conductivity ◽  
Inconel 718 ◽  
Performance Characteristics ◽  
Ultrasonic Power ◽  
Micro Edm ◽  
Machining Performance ◽  
Ultrasonic Assisted ◽  
Micro Holes ◽  
Inconel 718 Superalloy ◽  
Pulse On Time

Inconel 718 superalloy is widely used in aerospace industries for fabrication of the various components for aircraft engine because of its high strength at elevated temperature. It is an extremely difficult-to-machine material due to its work hardening nature and poor thermal conductivity. Creating micro-holes of high precision in this material is beyond the capability of conventional twist drill due to its low thermal conductivity. Micro-electrical discharge machining (micro-EDM) is a well-established process for the machining of any electrically conductive hard and brittle material, but due to very small feature size and narrow discharge gap, removal of debris becomes difficult, causes arcing and short-circuiting. In order to solve this problem, authors indigenously developed an innovative ultrasonic-assisted micro-EDM setup for workpiece vibration. The machining performance characteristics of Inconel 718 superalloy was studied using the developed setup in sinking configuration in terms of material removal rate (MRR), tool wear rate (TWR) and hole taper ([Formula: see text]) considering the effect of ultrasonic power, gap current, pulse on time and pulse off time. It was observed that higher ultrasonic power was more suitable for higher MRR, lower TWR and [Formula: see text]. It was also found from the results that 3 A gap current at 6[Formula: see text][Formula: see text]s pulse on time was appropriate for better MRR and 12[Formula: see text][Formula: see text]s pulse on time was more appropriate for low TWR and [Formula: see text]. The scanning electron microscope (SEM) analysis of created micro-holes was also performed with and without ultrasonic vibration to ensure the quality as well as accuracy.

The Effect of δ Phase on the Mechanical Properties of an Inconel 718 Superalloy

2012 ◽  
Vol 22 (5) ◽  
pp. 1512-1518 ◽  
Author(s):  
L. C. M. Valle ◽  
L. S. Araújo ◽  
S. B. Gabriel ◽  
J. Dille ◽  
L. H. de Almeida
Keyword(s):  
Mechanical Properties ◽  
Inconel 718 ◽  
Δ Phase ◽  
Inconel 718 Superalloy
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