Effect of annealing temperature on the microstructure evolution, mechanical and wear behavior of NiCr–WC–Co HVOF-sprayed coatings

Mazouzi, Azzeddine; Djerdjare, Boubekeur; Triaa, Salim; Rezzoug, Amine; Cheniti, Billel; Aouadi, Samir

doi:10.1557/jmr.2020.237

Cited by 9 publications

(6 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 12 shows a comparison between the microstructure of samples heat-treated for lower times and temperatures (e.g., at 500 °C for 30 min) and for higher times and temperatures (e.g., at 700 °C for 180 min) at the Interface. Most of all, it is worth noting that, while in the as-built condition the WC carbides appeared rounded with shattered edges, after heat treatment the newly formed carbides exhibit a polygonal geometry with well-defined boundaries, as already mentioned in [16,24]. Additionally, the presence of branched eutectic structures within this region has significantly decreased, being replaced by dense spongy agglomerates (highlighted in orange in Figure 12a).…”

Section: Microstructural Analysis Of Samples In Pfht Conditionsmentioning

confidence: 59%

“…Nevertheless, the local distribution of η-phase structures as well as the size and morphology of WC grains is altered, as proved by our SEM/EDS analysis. In [24], it was found that the higher the heat treatment temperature, the greater the extent of WC particle dissolution. In addition, the WC dissolution diffuses into the metallic matrix and forms another carbide phase and new eutectic phases.…”

Section: Microstructural Analysis Of Samples In Pfht Conditionsmentioning

confidence: 99%

“…The authors found that annealing temperatures in the range of 800-900 • C are sufficient to solubilize the η-phase and to improve the carbide distribution in the matrix. The impact of both annealing times and temperatures on the hardness, microstructure, and wear behavior of NiCr-WC-Co coatings fabricated by a high-velocity oxygen fuel technique was investigated by Mazouzi et al [24]; the authors demonstrated that when the annealing temperature is set up at 800 • C for 2 h, optimal mechanical and tribological properties can be obtained. Kumar et al [25] performed an optimization of the different annealing heat treatment temperatures on the Selective Laser Sintering (SLS) WC-17Co samples at fixed dwelling times.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of Post-Fabrication Heat Treatments on the Microstructure of WC-12Co Direct Energy Depositions

Morales,

Fortini,

Soffritti

et al. 2023

Coatings

View full text Add to dashboard Cite

Laser-Directed Energy Deposition (L-DED) is an additive manufacturing technique that has lately been employed to deposit coatings of cemented carbides, such as WC-Co. During deposition, complex microstructural phenomena usually occur, strongly affecting the microstructural and mechanical behavior of the coatings. Post-fabrication heat treatments (PFHTs) may be applied to homogenize and strengthen the microstructure; nevertheless, to the best of the authors’ knowledge, just a few papers deepened the effect of these treatments on cemented carbides fabricated by additive manufacturing. This work evaluates the influence of four PFHTs on the microstructural evolution and hardness of L-DED WC-12Co. For each treatment, different combinations of solubilization time and temperature (between 30 and 180 min and from 400 °C to 700 °C, respectively) were adopted. The microstructure was investigated by optical and scanning electron microscopy equipped with energy-dispersive spectroscopy, whereas the mechanical properties were determined by Vickers hardness measurements. Based on the results, high microstructural heterogeneity in terms of WC particles, η-phase structures, and Co distribution was observed in the sample in the as-built condition. Some cracking defects were also observed in the samples, irrespective of the heat treatment conditions. Finally, a finer microstructure and a lower amount of brittle ternary η-phase, together with an increase in hardness (1030 ± 95 HV10), were found for the highest dwelling times (180 min) and for solubilization temperatures in the range of 500–600 °C.

show abstract

Section: Microstructural Analysis Of Samples In Pfht Conditionsmentioning

confidence: 59%

Section: Microstructural Analysis Of Samples In Pfht Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Post-Fabrication Heat Treatments on the Microstructure of WC-12Co Direct Energy Depositions

Morales,

Fortini,

Soffritti

et al. 2023

Coatings

View full text Add to dashboard Cite

show abstract

“…The above results show that the hardness of the WC-12Co coating is high and the friction coefficient is relatively stable compared to the TC18 substrate which has a stronger anti-sheer ability. The WC phase in the powder significantly enhances the performance of the coating [33]. The wear profile curves of the TC18 substrate and the WC-12Co coating are shown in Figure 16.…”

Section: Wear Performance Researchmentioning

confidence: 99%

The Effect of High-Velocity Air-Fuel WC-12Co Coatings on the Wear and Corrosion Resistance of TC18 Titanium Alloy

et al. 2023

View full text Add to dashboard Cite

TC18 titanium alloy is an essential material for aircraft landing gear. To reveal the wear and corrosion mechanisms of landing gear in service, a WC-12Co coating on a TC18 substrate was prepared by High-Velocity Air-Fuel (HVAF) spraying based on optimized process parameters, and an analysis of the microscopic characterization results for the materials involved was performed. Based on the computational fluid dynamics (CFD) method, the combustion reaction and discrete phase models of HVAF spraying were established. The flame characteristics under compressible turbulence and the flight temperature and velocity of particles were calculated. The effect of the spraying parameters on the flight temperature and velocity of particles was evaluated based on the response surface method (RSM) through multiple groups of orthogonal experiments, and the optimized process parameters were determined. The mass flow rate of reactants was 0.051 kg/s, the oxygen/fuel ratio was 2.83, the mass flow rate of the nitrogen was 0.000325 kg/s, the pressure of oxygen and fuel inlet was 1 MPa, the pressure at the particles inlet was 0.6 MPa and the maximum temperature and velocity of spraying particles were 1572 K and 417 m/s, respectively. The coatings prepared with the optimized process were subjected to the Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS), X-Ray Diffraction (XRD), wear, hardness, artificial seawater soaking and neutral salt spray experiments. The results showed that the mean hardness of the TC18 substrate was 401.2 HV0.3, the mean hardness of the WC-12Co coating was 1121 HV0.3, the friction coefficient between the TC18 substrate and the Si3N4 ceramic ball was 0.55 and the friction coefficient between the WC-12Co coating and the Si3N4 ceramic ball was 0.4. Compared to the TC18 substrate, the hardness of the WC-12Co coating was increased by 720 HV0.3, the friction coefficient with the Si3N4 ceramic ball decreased by 0.11, the corrosion resistance significantly improved and the maximum depth of the corrosion pits was 5 μm. The properties of the TC18 titanium alloy were effectively improved by the WC-12Co coating. The results of this study provide guidance for surface protection technologies of aircraft landing gear.

show abstract

“…The fracture toughness of WC particles at 600 • C is higher than that at 200 • C and 400 • C, and the average crack length on the particles is relatively short, which is related to the degree of dissolution of WC particles. With the increase in impact temperature, the synergistic effect of the Ni binder and WC grain is conducive to releasing local stress due to the effect of thermal stress, thus improving the fracture toughness of the cemented carbide [31]. However, the fracture toughness of the Ni40A binder at 600 • C is poor, mainly due to the serious decomposition of the WC particles, which increases the hardness in the binder, and thus makes its fracture toughness lower than that at 200 • C and 400 • C. However, there are few cracks in the binder of the overall Ni40A.…”

Section: Fracture Toughness Of the Surfacing Layer After Impact Testsmentioning

confidence: 99%

Microstructure and Mechanical and Impact Behaviors of WC-Particle-Reinforced Nickel-Based Alloy Surfacing Layers at Evaluated Temperatures

Zhang

et al. 2023

Metals

View full text Add to dashboard Cite

A WC-particle-reinforced nickel-based alloy surfacing layer was fabricated on 42CrMo ultra-high-strength steel. The microstructure and the mechanical and impact-damage behaviors of the surfacing layers at the evaluated temperatures were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and the Vickers hardness tester. Results showed that these WC particles gradually changed from elongated and crisscross needle-like phases to blocks with the increase in impact temperature. Numerous carbide phases (e.g., (Cr,Ni,Fe)23C6) and γ-Ni phases were formed in the substrate matrix. The surfacing layer showed a typical brittle fracture, and the impact energy decreased with the increase in temperature. Moreover, the surfacing layer showed a clear quasi-cleavage fracture morphology without dimples after a 600 °C impact test but exhibited a mixture of dimple fractures and cleavage fractures after the 200 °C and 400 °C impact tests. The Vickers fracture toughness test showed that the average hardness of the surfacing layer after a 600 °C impact test was 383 HV1.0, which is about 0.8 times that after the 200 °C impact test. In addition, the WC particles in the surfacing layer after the 600 °C impact test showed the highest fracture toughness, but the corresponding Ni40A binder phase possessed the lowest fracture toughness.

show abstract

Effect of annealing temperature on the microstructure evolution, mechanical and wear behavior of NiCr–WC–Co HVOF-sprayed coatings

Abstract: Abstract

Cited by 9 publications

References 42 publications

Effect of Post-Fabrication Heat Treatments on the Microstructure of WC-12Co Direct Energy Depositions

Effect of Post-Fabrication Heat Treatments on the Microstructure of WC-12Co Direct Energy Depositions

The Effect of High-Velocity Air-Fuel WC-12Co Coatings on the Wear and Corrosion Resistance of TC18 Titanium Alloy

Microstructure and Mechanical and Impact Behaviors of WC-Particle-Reinforced Nickel-Based Alloy Surfacing Layers at Evaluated Temperatures

Contact Info

Product

Resources

About