| 1. |
- Ding, C., et al.
(författare)
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Study on fracture of the fibrous monolith cemented carbide
- 2013
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Ingår i: Advanced Materials Research. - 1662-8985 .- 1022-6680. ; 815, s. 43-47
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Konferensbidrag (refereegranskat)abstract
- A fibrous monolith cemented carbide with WC-6%Co as cell and WC-20%Co as cell boundaries was produced through hot co-extrusion process in this paper. The density, hardness, transverse rupture strength (TRS) and fracture toughness (KIc) of the fibrous monolith cemented carbide were tested, and the fracture and crack propagation were observed by metalloscope and Scanning Electron Microscope. The result shows fibrous monolith structure design could effectively improve the TRS and the KIc of WC/Co cemented carbide without a significant decrease of hardness. It is the reason of high transverse rupture strength and fracture toughness that WC-20%Co can absorb more fracture energy in order to slow, prevent, or deflect crack propagation, proved by metalloscope and scanning electron microscope.
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| 2. |
- Liu, X., et al.
(författare)
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Microstructure and mechanical properties of sintered fibrous monolith cemented carbide
- 2013
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Ingår i: Advanced Materials Research. - 1662-8985 .- 1022-6680. ; 815, s. 233-239
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Konferensbidrag (refereegranskat)abstract
- A fibrous monolith cemented carbide with WC-6Co as cell and WC-20Co as cell boundaries was produced through hot co-extrusion process in this paper. The density, hardness, bending strength and fracture toughness of the fibrous monolith cemented carbide were tested, and the fracture and crack propagation were observed by metalloscope and SEM. The results showed that the bending strength and fracture toughness of the fibrous monolith cemented carbides was remarkably improved 71.91% and 45.7% respectively, while the hardness was slightly decreased 1% compared with WC-6Co composites. It is the reason that the tougher shell WC-20Co with higher bending strength and fracture toughness can absorb more fracture energy, which can slow down and prevent the crack propagating from brittle core WC-6Co.
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| 3. |
- Gong, Karin Anne Xia, 1965, et al.
(författare)
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Ni3Al-based Intermetallic Alloys as A New Type of High-Temperature and Wear-Resistant Materials
- 2007
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Ingår i: Journal of Iron and Steel Research International. - 1006-706X. ; 14:5, Suppl. 1, s. 21-25
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Tidskriftsartikel (refereegranskat)abstract
- Some intermetallics as high-temperature wear-resistant materials attracted attention of material researchers due to their intrinsic long-range ordered crystalline structures with strong oriented atomic bonding. In the group, Ni3Al-based intermetallic alloys are especially interesting for certain tribological applications. In this work, the wear-behaviour of an existed Ni3Al-based alloy, 77.7Ni-9.8Al-11.5Fe-0.5Mn-0.5Ti-0.1B in weight percentage, and its composites reinforced by Cr3C2-particles were studied, and related to their microstructures. HIPing and casting processes were applied for preparing the materials. Wear-rate of the testing materials under different loads and their scuffing resistance were measured by Pin-on-Disk method. The tested materials were analysed by SEM, EDS, and XRD techniques. The results revealed that the single phase Ni3Al-based alloy showed a reasonable wear-resistance, compared to a duplex microstructure. And, the investigation also indicated that the hard Cr-carbide played a positive role on tribological intermetallics, especially for reducing the wear-rate.
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| 4. |
- Feng, S., et al.
(författare)
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Formation of In-Situ Dispersion Strengthening Particles in Cast FeCrAl Alloy
- 2010
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Ingår i: Journal of Iron and Steel Research International. - 1006-706X. ; 17:2, s. 74-78
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Tidskriftsartikel (refereegranskat)abstract
- In order to fabricate dispersion strengthened alloys strengthened by submicron-sized or nano-sized stable particles through casting routes, understanding of the formation process of dispersion strengthening particles in metal melt is of significance. Thus, nano NiO and TiO2 particles were selected as reactant to form in-situ dispersion strengthening oxide particles in Fe20Cr5Al alloy. Nano NiO and TiO2 particle powder was separately dispersed into nano Ni powder first. The loose mixed nano powder was added in Fe20Cr5Al alloy melt when pouring the melt into mold. The study shows that nano NiO particles were not as effective as nano TiO2 particles in forming dispersion strengthening Al2O3 particles. The final diameters of dispersion strengthening oxide particles arose from nano TiO2 particles were of submicron. The Brownian collision of particles had caused this coarsening.
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| 5. |
- Feng, Yingkai, et al.
(författare)
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Effect of Cr3C2 Content on the Microstructure and Wear Resistance of Fe3Al/Cr3C2 Composites
- 2022
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Ingår i: Coatings. - : MDPI AG. - 2079-6412. ; 12:12
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, an engine piston ring coating comprising composite material of Fe3Al and Cr3C2 mixed powder was prepared by laser cladding onto carbon structural steel. The microstructure and tribological properties of the cladding materials were investigated through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and wear tests. The influence mechanism of the Cr3C2 content in cladding powder was studied. During the process of wear, the soft Fe3Al/Fe2AlCr matrix is first ground off, and the hard Cr7C3 phase initially supports the abrasive surface before being worn away into hard particles, resulting in abrasive wear. With the increase in Cr3C2 content, the hardness of the cladding layer increases, the proportion of the Cr7C3 phase increases, and the morphology changes from a sparse network to a dense floccule. Of the cladding layers with different Cr3C2 content, the 15 wt.% Cr3C2 cladding layer had the lowest friction coefficient, and the 25 wt.% Cr3C2 cladding layer had the lowest wear rate. The low wear rate of the 25 wt.% Cr3C2 cladding layer can be attributed to the fact that adhesive wear does not easily occur and the fine microstructure of the strengthening phase, which facilitates better separation in the grinding surfaces.
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| 6. |
- Fu, L., et al.
(författare)
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Effects of Cr3C2 content and temperature on sliding friction and wear behaviors of Cr3C2/Ni3Al composite materials
- 2018
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Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 414-415, s. 163-173
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Tidskriftsartikel (refereegranskat)abstract
- Chromium carbide (Cr3C2)-reinforced Ni3Al matrix composites, which possess excellent high-temperature strength and wear resistance, are considered as potential high-temperature wear-resistant materials. In this study, effects of Cr3C2content on the friction and wear properties of Cr3C2/Ni3Al composites and their counterpart gray cast iron disks were investigated at different temperatures. The worn surface morphologies of the Cr3C2/Ni3Al composites and gray cast iron disks were analyzed to understand their wear mechanisms. The analysis results showed that in the Ni3Al matrix composites, a combination of abrasive wear and adhesive wear occurred at room temperature, whereas adhesive wear was severer at 200 °C. Furthermore, the optimum Cr3C2contents of the Cr3C2/Ni3Al composites were found to be 18 vol% and 12 vol% at room temperature and 200 °C, respectively. The volume loss of the composites increased with an increase in the fraction of the Cr3C2strengthening phase at 350 °C. The wear resistance of the gray cast iron disks decreased with an increase in temperature. In contrast, the wear resistance of the Ni3Al matrix composites increased with an increase in temperature. This increased wear resistance of the composites is attributed to the transformation of their wear mechanism with increasing temperature.
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| 7. |
- Fu, L. H., et al.
(författare)
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Influence of Cr3C2 content on the wear properties of Cr3C2/Ni3Al composites
- 2016
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Ingår i: Gongcheng Kexue Xuebao/Chinese Journal of Engineering. - 2095-9389. ; 38:8, s. 1145-1152
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Tidskriftsartikel (refereegranskat)abstract
- The Ni3Al-alloy and its composites with different Cr3C2 contents were fabricated by a hot isostatic pressing (HIP) technique. The influences of Cr3C2 content on the microstructure, hardness and wear properties of the Cr3C2/Ni3Al composites were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and wear tribometry. The results show that inter-diffusion occurs between the original Cr3C2 and the Ni3Al particles during the HIP process and the Cr3C2 particles partially transform into M7C3 (M=Cr, Fe, Ni) structures. Under specific friction and wear conditions, the wear resistance of the Cr3C2/Ni3Al composites is significantly improved due to the addition of Cr3C2 particles by about 4-10 times, compared to the Ni3Al alloy. In addition, the cutting and scraping effects of counter-part disks by the Cr3C2/Ni3Al composites decreases with increasing Cr3C2 addition, resulting in a reduction in wear rate of counter-part disks.
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| 8. |
- Fu, L. H., et al.
(författare)
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Microstructure and phases constitution of Cr3C2/Ni3Al composites prepared by hot isostatic pressing (HIP)
- 2016
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Ingår i: Journal of Iron and Steel Research. - 1001-0963. ; 28:12, s. 52-58
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Tidskriftsartikel (refereegranskat)abstract
- The Cr3Cj/Ni3Al composite materials were prepared by hot isostatic pressing (HIP) at 1160°C and 100MPa. Microstructure and phases constitution of the composite materials were investigated. The results indicate that the original Cr3C2 particle firstly dissolves into Cr and C atoms and then diffuses into the matrix. During the cooling process, the dissolved Cr and C atoms transformed into a stable Cr7C3 structure. Also, an uphill diffusion phenomenon is observed for Fe element from the matrix to the Cr7C3 carbide phase, which is attributed to the easy formation of stable carbides of Fe element in Ni3Al alloy with C element. And, the Fe atoms substitute a part of Cr atoms in Cr7C3 carbides and form a diffusion phase with M7 C3 (M for Cr, Fe) structure. When the original Cr3Q2 particles are large, it cannot be completely dissolved during the high temperature period. The undissolved core of Cr3C2 particles still remain the Cr3C2 structure after the cooling process. The Cr3C2/Ni3 Al composite materials are composed of Cr3C2 hard core phase, M7C3 diffusion phase and ?-Ni3Al matrix material phase. The Cr3C2 hard core phase and the ?'-Ni3Al matrix created a good diffusion bonding by the formed M7C3 diffusion phase. Therefore, the Cr3C2 particle on the worn surface does not peel off and the groove is interrupted around the chromium carbides during the wear test, resulting in significantly improved wear resistance of Cr3C2/Ni3Al composites.
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| 9. |
- Fu, L., et al.
(författare)
-
Wear mechanism of Cr 3 C 2 /Ni 3 Al composites showing excellent wear resistance
- 2019
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Ingår i: Gongcheng Kexue Xuebao/Chinese Journal of Engineering. - 2095-9389. ; 41:1, s. 117-123
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Tidskriftsartikel (refereegranskat)abstract
- The Ni 3 Al intermetallic compound is considered an excellent wear-resistant material. The addition of Cr 3 C 2 particles can further improve the wear resistance of Ni 3 Al-based alloys. In order to elucidate the wear mechanism of Cr 3 C 2 /Ni 3 Al composites improved by the Cr 3 C 2 strengthening phase, Ni 3 Al-alloy and Cr 3 C 2 /Ni 3 Al composites were prepared by the hot isostatic pressing process in this study. The mechanical properties and wear resistance of each phase in the Ni 3 Al-alloy and Cr 3 C 2 /Ni 3 Al composites were investigated using a nano-indentation instrument and a pin-on-disk friction and wear tester, respectively. The worn surface morphologies and the hardness of the subsurface layer under the worn surfaces of the Ni 3 Al-alloy and Cr 3 C 2 /Ni 3 Al composites were determined by a scanning electron microscopy (SEM) and a nano-indentation instrument. The results indicate that the hardness of the matrix phase in the Cr 3 C 2 /Ni 3 Al composites is significantly improved by the addition of Cr 3 C 2 particles. The nano-hardness and the elastic modulus of each phase in the Cr 3 C 2 /Ni 3 Al composites gradually increase from matrix phase through diffusion phase to hard core phase. The mechanical properties between the matrix, diffusion, and hard core phases in the Cr 3 C 2 /Ni 3 Al composites present a gradient transition. This kind of structure distribution is good for enhancing the wear resistance of Cr 3 C 2 /Ni 3 Al composite materials. As for friction and wear conditions in this study, abrasive wear was the dominant wear mechanism, which occurred on the surfaces of the Ni 3 Al-alloy and Cr 3 C 2 /Ni 3 Al composites. The Cr 3 C 2 /Ni 3 Al composites showed a good wear resistant property. The carbide-strengthening phase can block up the cutting action of the wear debris, reduce the interaction between the wear materials, and decrease the thickness of the subsurface layer and the size of the wear debris, resulting in improved wear resistance of Cr 3 C 2 /Ni 3 Al composites.
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| 10. |
- Gong, Karin Anne Xia, 1965, et al.
(författare)
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Toughening effect and oxidation behavior of MoSi2-ZrO2 composites
- 2006
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Ingår i: Boston,MA 2006,MRS Fall meeting; November27-December 1,Hynes Convention Center & Sheraton Boston Hotel Boston,MA. ; 980:0980-II05-35, s. 339-344
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- AbstractToughening effect of ZrO2-particles on MoSi2-based materials is one of the important toughening mechanism. In this work, the influence of particle size and volume percentage of unstabilized ZrO2-addition on toughening effect in MoSi2-matrix composites was studied. The measured data revealed that the fine particle size,
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