| 1. |
- 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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| 2. |
- Gong, Karin Anne Xia, 1965
(författare)
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Study of Ni3Al- and MoSi2-based Materials for High Temperature Structural Applications
- 2007
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In general, the potential of current conventional high-temperature materials has been exploited to a large extent. The industries are therefore looking forward to development of alternative materials for their industrials application, which would be lighter, stronger and having improved higher temperature potential compared to the presently available alloys. Among the various high temperature materials for the future, intermetallics-base alloys are prime candidates for alternative materials. In this thesis work, Ni3Al- and MoSi2-based materials were specially investigated for their industrial.On Ni3Al-based materials Attractive engineering properties of Ni3Al alloys is their increasing yield strength with increasing temperature up to about 650-750 ºC. This type of strength behaviour suggested that the Ni3Al-based intermetallic alloys may have good wear properties in the peak-strength temperature range. Consequently, investigations of their sliding friction and wear were initiated. In fact, a number of laboratory studies have indicated that Ni3Al-based alloys have significant potential in wear-critical applications, especially in cavitations erosion and in sliding wear at the temperature range between 400 ºC and 650 ºC. In this work, an existed Ni3Al-based alloy 77.7Ni-9.8Al-11.5Fe-0.5Mn-0.5Ti-0.1B in weight percentages and its composite reinforced by 6 vol. % Cr3C2-particles were studied and related to their microstructures. Hot isostatic pressing and casting were applied for preparing the materials. Wear rate of the test materials under different loads and their scuffing resistance were measured by Pin-on-Disk method. SEM, EDS, XRD, and EBSD techniques were used to observe the microstructures and identify the phase constitutions of the tested materials. The tribological performance related to the analytical results revealed that the single phase Ni3Al-based alloy showed a better wear-resistance compared to duplex microstructure. And the investigation also indicated that the hard Cr-carbide played a positive role on tribological intermetallics reducing the wear-rate.On MoSi2-based materialsMoSi2 is presently considered as one of the most promising due to its high melting point (2030ºC) and excellent elevated-temperature oxidation resistance. However, like most of other intermetallics, the major problem, which has impeded their use, as high temperature materials, is their poor ductility and toughness during brittle-to-ductile transition temperature, BDTT, and low strength level above at temperature. In other words, their low temperature strength is limited by brittle fracture while the high temperature strength is governed by plastic flow. From the earlier investigations it was clear that the addition of alloying elements could not make the monolithic MoSi2 compound having the right combination of ambient temperature toughness and high temperature strengthen. For the most demand depends on the development of engineered composite materials.In this work, the attention was mostly focused on ZrO2-particles reinforced MoSi2-matrix composites. The working results indicated (1) a PLS process could be a practical and economical method for producing MoSi2-ZrO2 composites; (2) ZrO2-particles of less than 1 μm usually generated the better sintered density, RT-hardness and toughness than of the composites compared with the bigger particles; (3) the composites containing 15 – 25 vol.% unstable zironia (USZ) showed a better toughening effect, compared to the composites having less or more particles; and (4) A deteriorated oxidation resistance of MoSi2-ZrO2 composite compared to its monolithic counterpart is due to the formation of the porous oxide layer of ZrSiO4+SiO2 mixture and a retarded Si diffusion by the inner oxidation and reaction between SiO2 and ZrSiO4. Therefore, an alloying addition for further forming a protective oxide layer is necessary on developing this type of composites.Keywords: Intermetallics, Ni3Al, MoSi2, High temperature materials, Wear-resistant materials, Composites, Toughening.
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| 3. |
- 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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| 4. |
- Gong, Karin Anne Xia, 1965, et al.
(författare)
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Toughening Effect and Oxidation Behavior of MoSi2-ZrO2 Composites
- 2007
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Ingår i: Materials Research Society Symposium Proceedings. - 0272-9172. ; 980, s. 339-344
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Tidskriftsartikel (refereegranskat)abstract
- Toughening effect of ZrO2-particles on MoSi2-based materials is one of the important toughening mechanisms. In this work, the influence of particle size and volume percentage of unstabilized ZrO2-addition on toughening in MoSi2-matrix composites was studied. The measured data revealed that the fine particle size,
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| 5. |
- Gong, Karin Anne Xia, 1965
(författare)
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Wear Behaviour Related to Microstructure of Ni3Al-Based Alloys
- 2006
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Ingår i: Materials Research Society Symposium Proceedings Volume 980. ; 980
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A number of laboratory studies have indicated that Ni3Al-based alloys have significant potential in wear-critical applications, especially in sliding wear in a temperature range of between 400 ºC - 650 ºC. In this study, the wear behavior of an iron-alloyed Ni3Al with composition of Ni-18.8Al-10.7Fe-0.5Mn-0.5Ti-0.2B in atomic percentage and its composites reinforced by 6 vol. % Cr3C2-particles were investigated. Hot isostatic pressing (HIP) and casting processes were applied for preparing the materials. The wear rate of the tested materials under different loads and their scuffing resistance were measured by means of the Pin-on-Disk method. Analytical SEM, EDS, and XRD techniques were used to observe the microstructures and identify the phase constitutions of the materials. The tribological performance related to the analytical results revealed that the single phase Ni3Al-based alloy showed an improved scuffing resistance, compared to a duplex phase microstructure. Also, the investigation indicated that the added hard Cr-carbide played a positive role for the tribological behavior of the intermetallics, especially in terms of reducing the wear rate.
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| 6. |
- Gong, Karin Anne Xia, 1965, et al.
(författare)
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Wear of Ni3Al-based materials and its chromium-carbide reinforced composites
- 2008
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Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 265:11-12, s. 1751-1755
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Tidskriftsartikel (refereegranskat)abstract
- A number of laboratory studies have indicated that Ni3Al-based alloys have significant potential in wear-critical applications, especially in sliding wear in a temperature range between 400 and 650 °C. In this study, the wear behavior of an iron-alloyed Ni3Al with composition of Ni–18.8Al–10.7Fe–0.5Mn–0.5Ti–0.2B in atomic percentage and its composites reinforced by 6 vol.% Cr3C2-particles were investigated.Hot isostatic pressing (HIP) and casting processes were applied for preparing the materials. The wear rate of the tested materials under different loads and their scuffing resistance were measured by means of the pin-on-disc method. Analytical SEM, EDS, and XRD techniques were used to observe the microstructures and identify the phase constitutions of the materials. The tribological performance related to the analytical results revealed that the single-phase Ni3Al-based alloy showed an improved scuffing resistance, compared to a duplex-phase microstructure. Also, the investigation indicated that the added hard Cr-carbide played a positive role for the tribological behavior of the intermetallics, especially in terms of reducing the wear rate.
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| 7. |
- Luo, H. L., et al.
(författare)
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Abrasive wear comparison of Cr3C2/Ni3Al composite and stellite 12 alloy cladding
- 2007
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Ingår i: Journal of Iron and Steel Research International. - 1006-706X. ; 14, s. 15-20
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Tidskriftsartikel (refereegranskat)abstract
- The room-temperature abrasive wear resistance of Cr3C2/Ni3Al composite and Stellite12 alloy cladding was investigated. Three kinds of tests, designed for different load and abrasive' size, were utilized to understand the wear behaviour of these materials. Under all three wear conditions, the abrasion resistance of Cr3C2/Ni3Al composite cladding is much higher than Stellite 12 alloy. In addition, the wear-resistant advantage of Cr3C2/Ni3Al composite is more obvious when the size of the abrasive is small. The relative wear resistance of Cr3C2/Ni3Al composite increases from 2.44 times to 6 times when the size of the abrasive decreases from 180 mu m to 50 mu m. The good wear resistance of Cr3C2/Ni3Al composite cladding can be mainly attributed to the high hardness, large volume fraction of reinforcement, large reinforcement particles, and size distribution of reinforcement.
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