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.
Table 1
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% Gr | 950 | 40 | 100 | 5 |
| 33% Inconel, 10% WC, 45% Co, and 12% Gr | 1,000 | 45 | 100 | 5 |
| 90 wt% Inconel, 4 wt% WC, 5 wt% Co, and 1 wt% Gr | 1,050 | 50 | 100 | 5 |
Figure 2
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).
Figure 4
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).
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.
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.
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.
Figure 9
Relation between the micro-hardness and relative density of compositions A, B, C, and D.
Table 2
Micro-hardness and relative density percentages of sintered composites.
| Notation of specimen | Hardness (HV) | Relative density (%) |
|---|---|---|
| A | 368 ± 3 | 96.7 ± 0.3 |
| B | 340 ± 3 | 94.6 ± 0.4 |
| C | 380 ± 4 | 97.8 ± 0.2 |
| D | 370 ± 3 | 97.0 ± 0.3 |
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.
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.
Table 3
Trials of micro tensile test on specimens A, B, C, and D. Bold value significantly shows the Specimen D tensile stress is maximum.
| Specimen | Maximum tensile stress at ambient temperature (MPa) | Maximum tensile stress at 450°C temperature (MPa) | ||||||
|---|---|---|---|---|---|---|---|---|
| Trial 1 | Trial 2 | Trial 3 | Average | Trial 1 | Trial 2 | Trial 3 | Average | |
| A | 741 | 701 | 689.7 | 710.6 | 674.5 | 640.9 | 624 | 646.5 |
| B | 336.3 | 346 | 386 | 356.1 | 362.3 | 336 | 311 | 336.4 |
| C | 496.3 | 463 | 511 | 490.1 | 425.3 | 384.2 | 399.8 | 403.1 |
| D | 763.4 | 673.4 | 729.8 | 722.2 | 691.1 | 611.2 | 688.7 | 663.6 |
Figure 12
(a) SEM morphology of the fracture surface area of specimen D at room temperature. (b) Specimen D at 450°C.