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Development and characterization of graphene-reinforced Inconel 825 composite alloy for high temperature applications Cover

Development and characterization of graphene-reinforced Inconel 825 composite alloy for high temperature applications

Materials Science-Poland
Volume 43 (2025): Issue 2 (June 2025)
By: Sivakumar Ponmalai and  Dhavamani Chinnathambi  
Open Access
|Jun 2025

Figures & Tables

Figure 1

(a) SEM image of a specimen with compositions of Inconel 825, tungsten carbide (WC), cobalt (Co), and nanographene (Gr) powder. (b) Energy dispersive X-ray analysis (EDAX) spectrum of powder.
(a) SEM image of a specimen with compositions of Inconel 825, tungsten carbide (WC), cobalt (Co), and nanographene (Gr) powder. (b) Energy dispersive X-ray analysis (EDAX) spectrum of powder.

Figure 2

Image of tensile specimen.
Image of tensile specimen.

Figure 3

(a–d) Specimen prepared via SPS method. (a) Layer-by-layer sintered specimen (94.85 wt% Inconel–4.5 wt% WC–0.5 wt% Co–0.15 wt% Gr), (b) uniformly mixed specimen (45 wt% Inconel–10 wt% WC–33 wt% Co–12 wt% Gr), (c) high cobalt content specimen (33 wt% Inconel–10 wt% WC–45 wt% Co–12 wt% Gr), and (d) high Inconel content specimen (90 wt% Inconel–4 wt% WC–5 wt% Co–1 wt% Gr).
(a–d) Specimen prepared via SPS method. (a) Layer-by-layer sintered specimen (94.85 wt% Inconel–4.5 wt% WC–0.5 wt% Co–0.15 wt% Gr), (b) uniformly mixed specimen (45 wt% Inconel–10 wt% WC–33 wt% Co–12 wt% Gr), (c) high cobalt content specimen (33 wt% Inconel–10 wt% WC–45 wt% Co–12 wt% Gr), and (d) high Inconel content specimen (90 wt% Inconel–4 wt% WC–5 wt% Co–1 wt% Gr).

Figure 4

SEM image of a single particle of Inconel 825.
SEM image of a single particle of Inconel 825.

Figure 5

Optical metallographic image (magnification of 200×) of a powder particle sintered etched cross-section showing the microstructure of (a) uniformly mixed specimen (45 wt% Inconel–10 wt% WC–33 wt% Co–12 wt% Gr), (b) high cobalt content specimen (33 wt% Inconel–10 wt% WC–45 wt% Co–12 wt% Gr), and (c) high Inconel content specimen (90 wt% Inconel–4 wt% WC–5 wt% Co–1 wt% Gr).
Optical metallographic image (magnification of 200×) of a powder particle sintered etched cross-section showing the microstructure of (a) uniformly mixed specimen (45 wt% Inconel–10 wt% WC–33 wt% Co–12 wt% Gr), (b) high cobalt content specimen (33 wt% Inconel–10 wt% WC–45 wt% Co–12 wt% Gr), and (c) high Inconel content specimen (90 wt% Inconel–4 wt% WC–5 wt% Co–1 wt% Gr).

Figure 6

SEM of specimens for phase distribution and grain boundaries: after sintering, (a and b) 45 wt% Inconel, 10 wt% WC, 33 wt% Co, and 12 wt% graphene; (c and d) 33 wt% Inconel, 10 wt% WC, 45 wt% Co, and 12 wt% grapheme, and (e and f) 90 wt% Inconel, 4 wt% WC, 5 wt% Co & 1 wt% graphene.
SEM of specimens for phase distribution and grain boundaries: after sintering, (a and b) 45 wt% Inconel, 10 wt% WC, 33 wt% Co, and 12 wt% graphene; (c and d) 33 wt% Inconel, 10 wt% WC, 45 wt% Co, and 12 wt% grapheme, and (e and f) 90 wt% Inconel, 4 wt% WC, 5 wt% Co & 1 wt% graphene.

Figure 7

(a) 90 wt% Inconel, 4 wt% WC, 5 wt% Co, and 1 wt% graphene. EDAX element mapping in specimen D. (b) 45 wt% Inconel, 10 wt% WC, 33 wt% Co, and 12 wt% graphene. (c) 33 wt% Inconel, 10 wt% WC, 45 wt% Co, and 12 wt% graphene.
(a) 90 wt% Inconel, 4 wt% WC, 5 wt% Co, and 1 wt% graphene. EDAX element mapping in specimen D. (b) 45 wt% Inconel, 10 wt% WC, 33 wt% Co, and 12 wt% graphene. (c) 33 wt% Inconel, 10 wt% WC, 45 wt% Co, and 12 wt% graphene.

Figure 8

(a)–(h) EDAX area color mapping of the sample with 90 wt% Inconel, 4 wt% WC, 5 wt% Co, and 1 wt% graphene.
(a)–(h) EDAX area color mapping of the sample with 90 wt% Inconel, 4 wt% WC, 5 wt% Co, and 1 wt% graphene.

Figure 9

Relation between the micro-hardness and relative density of compositions A, B, C, and D.
Relation between the micro-hardness and relative density of compositions A, B, C, and D.

Figure 10

(a) Stress–strain curve of the samples tested at ambient temperature and (b) ultimate tensile strength and tensile modulus of the samples at ambient temperature.
(a) Stress–strain curve of the samples tested at ambient temperature and (b) ultimate tensile strength and tensile modulus of the samples at ambient temperature.

Figure 11

(a) Stress–strain curve at 450°C. (b) Ultimate tensile strength and tensile modulus of compositions A, B, C, and D at 450°C.
(a) Stress–strain curve at 450°C. (b) Ultimate tensile strength and tensile modulus of compositions A, B, C, and D at 450°C.

Figure 12

(a) SEM morphology of the fracture surface area of specimen D at room temperature. (b) Specimen D at 450°C.
(a) SEM morphology of the fracture surface area of specimen D at room temperature. (b) Specimen D at 450°C.

Processing parameters for sintering the composites_

Sintering details
Alloy/composites (wt%)Temperature (°C)Pressure (MPa)Heating rate (°C/min)Wetting time (min)
45% Inconel, 10% WC, 33% Co, and 12% Gr950401005
33% Inconel, 10% WC, 45% Co, and 12% Gr1,000451005
90 wt% Inconel, 4 wt% WC, 5 wt% Co, and 1 wt% Gr1,050501005

Trials of micro tensile test on specimens A, B, C, and D_ Bold value significantly shows the Specimen D tensile stress is maximum_

SpecimenMaximum tensile stress at ambient temperature (MPa)Maximum tensile stress at 450°C temperature (MPa)
Trial 1Trial 2Trial 3AverageTrial 1Trial 2Trial 3Average
A741701689.7710.6674.5640.9624646.5
B336.3346386356.1362.3336311336.4
C496.3463511490.1425.3384.2399.8403.1
D763.4673.4729.8 722.2 691.1611.2688.7 663.6

Micro-hardness and relative density percentages of sintered composites_

Notation of specimenHardness (HV)Relative density (%)
A368 ± 396.7 ± 0.3
B340 ± 394.6 ± 0.4
C380 ± 497.8 ± 0.2
D370 ± 397.0 ± 0.3
DOI: https://doi.org/10.2478/msp-2025-0019 | Journal eISSN: 2083-134X | Journal ISSN: 2083-1331
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Language: English
Page range: 63 - 77
Submitted on: Dec 5, 2024
Accepted on: Jun 12, 2025
Published on: Jun 30, 2025
Published by: Wroclaw University of Science and Technology
In partnership with: Paradigm Publishing Services
Publication frequency: 4 issues per year
Keywords:
spark plasma sintering,
micro-hardness,
tensile embrittlement,
surface morphology,
Inconel 825,
graphene,
tungsten carbide,
SEM EDAX
Related subjects:
Materials sciences,
Materials sciences, other,
Nanomaterials,
Functional and smart materials,
Materials characterization and properties

© 2025 Sivakumar Ponmalai, Dhavamani Chinnathambi, published by Wroclaw University of Science and Technology
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

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