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Zhaohui Chen - One of the best experts on this subject based on the ideXlab platform.
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Fabrication and characterization of ZrC foam by Melt Infiltration
Journal of Alloys and Compounds, 2017Co-Authors: Jinming Jiang, Song Wang, Zhaohui ChenAbstract:Abstract A new ultra-high temperature ceramic foam was developed with carbon foam template and zirconium alloy by adopting Melt Infiltration in this work. The obtained ZrC foam was highly macro-porous with low density and open cell structure, in which the pore diameter ranged from 400 to 520 μm with a mean value of 465 μm. Microstructural formation mechanism of the ZrC foam by Infiltration was analyzed. With an open porosity of 75.38% and a density of 1.35 g/cm 3 , the composite foam possessed a high compressive strength of 26.5 ± 6.28 MPa. Moreover, the thermal conductivity of ZrC foam ranged from 40.411 W m −1 K −1 to 9.102 W m −1 K −1 from ambient to 1200 °C.
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fabrication of cf zrc sic composites using zr 8 8si alloy by Melt Infiltration
Ceramics International, 2015Co-Authors: Jinming Jiang, Song Wang, Zhaohui ChenAbstract:Abstract Cf/ZrC–SiC composites were fabricated by Melt Infiltration at 1800 °C using Zr–8.8Si alloy and carbon felt preforms. Microstructural analysis showed the formation of both ZrC and SiC phases in the matrix, in which ZrC acted as a main composition of the resulting composites. The results showed that carbon matrix reacted preferentially with Si of Zr–8.8Si alloy, which caused the formation of SiC first and then ZrC. The designed carbon coating by pyrolysis prevented the severe reaction between fibers and the Melt. The composites could be more dense and uniform with the bending strength of 53.3 MPa, when preforms had a high open porosity (47.2%) with small size pores (10–40 μm).
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Fabrication of Cf/ZrC–SiC composites using Zr–8.8Si alloy by Melt Infiltration
Ceramics International, 2015Co-Authors: Jinming Jiang, Song Wang, Zhaohui ChenAbstract:Abstract Cf/ZrC–SiC composites were fabricated by Melt Infiltration at 1800 °C using Zr–8.8Si alloy and carbon felt preforms. Microstructural analysis showed the formation of both ZrC and SiC phases in the matrix, in which ZrC acted as a main composition of the resulting composites. The results showed that carbon matrix reacted preferentially with Si of Zr–8.8Si alloy, which caused the formation of SiC first and then ZrC. The designed carbon coating by pyrolysis prevented the severe reaction between fibers and the Melt. The composites could be more dense and uniform with the bending strength of 53.3 MPa, when preforms had a high open porosity (47.2%) with small size pores (10–40 μm).
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Preparation of ZrB2 based composites by reactive Melt Infiltration at relative low temperature
Materials Letters, 2011Co-Authors: Shouming Zhang, Song Wang, Yulin Zhu, Zhaohui ChenAbstract:Abstract ZrB 2 based composites were prepared by a novel reactive Melt Infiltration process. The porous boron bars were used as preforms and infiltrated by the low Melting Zr 2 Cu intermetallic compound. Thermodynamics calculations revealed that B could react with liquid Zr 2 Cu to form ZrB 2 as low as 1100 °C. Composites were prepared by heating the two materials to 1200 °C for 3 h in vacuum. The resultant composites were studied with XRD and SEM. ZrB 2 was identified to be the main constituent. The composites had a flexural strength of 414.3 MPa, a flexural modulus of 183.6 GPa, and a fracture toughness of 5.5 MPa m 1/2 .
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Fabrication of W-ZrC Cermets by Reactive Melt Infiltration with Polycarbosilane as Preforms’ Adhesive
Materials Science Forum, 2011Co-Authors: Shouming Zhang, Song Wang, Yulin Zhu, Zhaohui ChenAbstract:Polycarbosilane (PCS) was introduced into preforms to prepare W-ZrC cermets by reactive Melt Infiltration (RMI). Properties and microstructure of the preforms and cermets were analyzed with XRD, SEM and EDS. The preforms had an open porosity of 42.0 %, and the WC particles were cemented by the pyrolysate of PCS. W-ZrC cermets were prepared by heating Zr2Cu covered preforms to 1300 °C for 3 h. XRD revealed that the resulting cermets were made up of W, ZrC and W2C. The cermets had an open porosity of 3.5 %, a flexural strength of 354.0 MPa, a flexural modulus of 192.5 GPa and a flexural toughness of 5.72 MPa·m1/2 .
R. Subramanian - One of the best experts on this subject based on the ideXlab platform.
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FeAl-TiC and FeAl-WC composites-Melt Infiltration processing, microstructure and mechanical properties
Materials Science and Engineering: A, 1998Co-Authors: R. Subramanian, Joachim H. SchneibelAbstract:Abstract TiC-based and WC-based cermets were processed with iron aluminide, an intermetallic, as a binder by pressureless Melt Infiltration to near full density (>97% TD). Phase equilibria calculations in the quaternary Fe–Al–Ti–C and Fe–Al–W–C systems at 1450°C were performed to determine the solubility of the carbide phases in liquid iron aluminide. This was done by using Thermocalc™ and the results show that molten Fe–40 at.% Al in equilibrium with Ti 0.512 C 0.488 and graphite, dissolves 4.9 at.% carbon and 64 at. ppm titanium. In the Fe–Al–W–C system, liquid Fe–40 at.% Al in equilibrium with graphite dissolves ≈5 at.% carbon and 1 at.% tungsten. Due to the low values for the solubility of the carbide phases in liquid iron aluminide, liquid phase sintering of mixed powders does not yield a dense, homogenous microstructure for carbide volume fractions greater than 0.70. Melt Infiltration of molten FeAl into TiC and WC preforms serves as a successful approach to process cermets with carbide contents ranging from 70 to 90 vol.%, to greater than 97% TD. Also, the microstructures of cermets prepared by Melt Infiltration were very homogenous. Typical properties such as hardness, bend strength and fracture toughness are reported. SEM observations of fracture surfaces suggest the improved fracture toughness to result from the ductility of the intermetallic phase. Preliminary experiments for the evaluation of the oxidation resistance of iron aluminide bonded cermets indicate that they are more resistant than WC–Co cermets.
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FeAl-TiC cermets—Melt Infiltration processing and mechanical properties
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 1997Co-Authors: R. Subramanian, Joachim H. SchneibelAbstract:Abstract TiC-based cermets were processed with iron aluminide, an intermetallic, as a binder by pressureless Melt Infiltration to near full density (>97% theoretical density). Phase equilibria calculations in the quaternary Fe–Al–Ti–C system at 1723 K by Thermocalc™ were performed to determine the solubility of TiC in liquid iron aluminide. Results show that molten Fe–40at.%Al in equilibrium with Ti 0.512 C 0.488 and graphite, dissolves 4.9 at.% carbon and 64 atomic ppm titanium. Due to the low values for the solubility of the carbide phases in liquid iron aluminide, Melt Infiltration of molten FeAl into TiC preforms is more successful than conventional liquid phase sintering to process cermets with carbide contents ranging from 70 to 90 vol.%, to greater than 97% of theoretical density. Hardness, bend strength and fracture toughness are reported. SEM observations of fracture surfaces suggest the improved fracture toughness to result from the ductility of the intermetallic phase. Evaluation of room temperature fracture toughnesses showed that relatively high fracture toughnesses (18 MPa m 1/2 ) can be obtained with iron aluminide as a binder. A systematic correlation of the ligament sizes with the fracture mode was performed. The results clearly show that FeAl ligaments larger than about 1.2 μm fracture by cleavage and those smaller in size fracture predominantly in a ductile manner. Slow crack growth experiments were performed with specimens immersed in water and in an oxygen atmosphere. The extent of environmental embrittlement was evaluated by comparing the work to fracture in water and oxygen, respectively. With additions of more than 20–40 vol.% TiC, the composites showed only small differences in the work of fracture, indicating that environmental embrittlement of iron aluminide is not severe when it is used as a binder in cermets.
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Melt-Infiltration processing of TiC/Ni_3Al composites
Journal of Materials Research, 1997Co-Authors: K. P. Plucknett, P. F. Becher, R. SubramanianAbstract:A simple Melt-Infiltration processing route has been developed for the fabrication of TiC/Ni_3Al ceramic/intermetallic composites, which involves a combination of Infiltration and subsequent liquid phase sintering. For Ni_3Al contents from 8 to 25 vol. %, densities in excess of 98% of theoretical are readily obtained when processing at 1450 °C. TiC and Ni_3Al are the only phases detected in the densified materials. Ni3Al ductility is retained after processing, leading to the possibility of ductile phase toughened TiC composites for elevated temperature applications (up to ~1100 °C).
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FeAl-TiC and FeAl-WC composites - Melt Infiltration processing, microstructure and mechanical properties
1997Co-Authors: R. Subramanian, Joachim H. SchneibelAbstract:TiC-based and WC-based cermets were processed with iron aluminide, an intermetallic, as a binder by pressureless Melt Infiltration to near full density (> 97 % theoretical density). Phase equilibria calculations in the quaternary Fe-Al-Ti-C and Fe-Al-W-C systems at 145{degrees}C were performed to determine the solubility of the carbide phases in liquid iron aluminide. This was done by using Thermocalc{trademark} and the results show that molten Fe-40 at.% Al in equilibrium with Ti{sub 0.512}C{sub 0.488} and graphite, dissolves 4.9 at% carbon and 64 atomic ppm titanium. In the Fe-Al-W-C system, liquid Fe-40 at.% Al in equilibrium with graphite dissolves about 5 at.% carbon and 1 at.% tungsten. Due to the low values for the solubility of the carbide phases in liquid iron aluminide, liquid phase sintering of mixed powders does not yield a dense, homogeneous microstructure for carbide volume fractions greater than 0.70. Melt Infiltration of molten FeAl into TiC and WC preforms serves as a successful approach to process cermets with carbide contents ranging from 70 to 90 vol. %, to greater than 97% of theoretical density. Also, the microstructures of cermets prepared by Melt Infiltration were very homogeneous. Typical properties such as hardness, bend strength and fracture toughness are reported. SEM observations of fracture surfaces suggest the improved fracture toughness to result from the ductility of the intermetallic phase. Preliminary experiments for the evaluation of the oxidation resistance of iron aluminide bonded cermets indicate that they are more resistant than WC-Co cermets.
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Melt-Infiltration Processing of TiC/Ni3Al Composites
Journal of Materials Research, 1997Co-Authors: K. P. Plucknett, P. F. Becher, R. SubramanianAbstract:A simple Melt-Infiltration processing route has been developed for the fabrication of TiC/Ni{sub 3}Al ceramic/intermetallic composites, which involves a combination of Infiltration and subsequent liquid phase sintering. For Ni{sub 3}Al contents from 8 to 25 vol. {percent}, densities in excess of 98{percent} of theoretical are readily obtained when processing at 1450{degree}C. TiC and Ni{sub 3}Al are the only phases detected in the densified materials. Ni{sub 3}Al ductility is retained after processing, leading to the possibility of ductile phase toughened TiC composites for elevated temperature applications (up to {approximately}1100{degree}C). {copyright} {ital 1997 Materials Research Society.}
Song Wang - One of the best experts on this subject based on the ideXlab platform.
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Fabrication and characterization of ZrC foam by Melt Infiltration
Journal of Alloys and Compounds, 2017Co-Authors: Jinming Jiang, Song Wang, Zhaohui ChenAbstract:Abstract A new ultra-high temperature ceramic foam was developed with carbon foam template and zirconium alloy by adopting Melt Infiltration in this work. The obtained ZrC foam was highly macro-porous with low density and open cell structure, in which the pore diameter ranged from 400 to 520 μm with a mean value of 465 μm. Microstructural formation mechanism of the ZrC foam by Infiltration was analyzed. With an open porosity of 75.38% and a density of 1.35 g/cm 3 , the composite foam possessed a high compressive strength of 26.5 ± 6.28 MPa. Moreover, the thermal conductivity of ZrC foam ranged from 40.411 W m −1 K −1 to 9.102 W m −1 K −1 from ambient to 1200 °C.
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fabrication of cf zrc sic composites using zr 8 8si alloy by Melt Infiltration
Ceramics International, 2015Co-Authors: Jinming Jiang, Song Wang, Zhaohui ChenAbstract:Abstract Cf/ZrC–SiC composites were fabricated by Melt Infiltration at 1800 °C using Zr–8.8Si alloy and carbon felt preforms. Microstructural analysis showed the formation of both ZrC and SiC phases in the matrix, in which ZrC acted as a main composition of the resulting composites. The results showed that carbon matrix reacted preferentially with Si of Zr–8.8Si alloy, which caused the formation of SiC first and then ZrC. The designed carbon coating by pyrolysis prevented the severe reaction between fibers and the Melt. The composites could be more dense and uniform with the bending strength of 53.3 MPa, when preforms had a high open porosity (47.2%) with small size pores (10–40 μm).
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Fabrication of Cf/ZrC–SiC composites using Zr–8.8Si alloy by Melt Infiltration
Ceramics International, 2015Co-Authors: Jinming Jiang, Song Wang, Zhaohui ChenAbstract:Abstract Cf/ZrC–SiC composites were fabricated by Melt Infiltration at 1800 °C using Zr–8.8Si alloy and carbon felt preforms. Microstructural analysis showed the formation of both ZrC and SiC phases in the matrix, in which ZrC acted as a main composition of the resulting composites. The results showed that carbon matrix reacted preferentially with Si of Zr–8.8Si alloy, which caused the formation of SiC first and then ZrC. The designed carbon coating by pyrolysis prevented the severe reaction between fibers and the Melt. The composites could be more dense and uniform with the bending strength of 53.3 MPa, when preforms had a high open porosity (47.2%) with small size pores (10–40 μm).
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Preparation of ZrB2 based composites by reactive Melt Infiltration at relative low temperature
Materials Letters, 2011Co-Authors: Shouming Zhang, Song Wang, Yulin Zhu, Zhaohui ChenAbstract:Abstract ZrB 2 based composites were prepared by a novel reactive Melt Infiltration process. The porous boron bars were used as preforms and infiltrated by the low Melting Zr 2 Cu intermetallic compound. Thermodynamics calculations revealed that B could react with liquid Zr 2 Cu to form ZrB 2 as low as 1100 °C. Composites were prepared by heating the two materials to 1200 °C for 3 h in vacuum. The resultant composites were studied with XRD and SEM. ZrB 2 was identified to be the main constituent. The composites had a flexural strength of 414.3 MPa, a flexural modulus of 183.6 GPa, and a fracture toughness of 5.5 MPa m 1/2 .
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Fabrication of W-ZrC Cermets by Reactive Melt Infiltration with Polycarbosilane as Preforms’ Adhesive
Materials Science Forum, 2011Co-Authors: Shouming Zhang, Song Wang, Yulin Zhu, Zhaohui ChenAbstract:Polycarbosilane (PCS) was introduced into preforms to prepare W-ZrC cermets by reactive Melt Infiltration (RMI). Properties and microstructure of the preforms and cermets were analyzed with XRD, SEM and EDS. The preforms had an open porosity of 42.0 %, and the WC particles were cemented by the pyrolysate of PCS. W-ZrC cermets were prepared by heating Zr2Cu covered preforms to 1300 °C for 3 h. XRD revealed that the resulting cermets were made up of W, ZrC and W2C. The cermets had an open porosity of 3.5 %, a flexural strength of 354.0 MPa, a flexural modulus of 192.5 GPa and a flexural toughness of 5.72 MPa·m1/2 .
K. P. Plucknett - One of the best experts on this subject based on the ideXlab platform.
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Melt-Infiltration processing of TiC/Ni_3Al composites
Journal of Materials Research, 1997Co-Authors: K. P. Plucknett, P. F. Becher, R. SubramanianAbstract:A simple Melt-Infiltration processing route has been developed for the fabrication of TiC/Ni_3Al ceramic/intermetallic composites, which involves a combination of Infiltration and subsequent liquid phase sintering. For Ni_3Al contents from 8 to 25 vol. %, densities in excess of 98% of theoretical are readily obtained when processing at 1450 °C. TiC and Ni_3Al are the only phases detected in the densified materials. Ni3Al ductility is retained after processing, leading to the possibility of ductile phase toughened TiC composites for elevated temperature applications (up to ~1100 °C).
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Melt-Infiltration Processing of TiC/Ni3Al Composites
Journal of Materials Research, 1997Co-Authors: K. P. Plucknett, P. F. Becher, R. SubramanianAbstract:A simple Melt-Infiltration processing route has been developed for the fabrication of TiC/Ni{sub 3}Al ceramic/intermetallic composites, which involves a combination of Infiltration and subsequent liquid phase sintering. For Ni{sub 3}Al contents from 8 to 25 vol. {percent}, densities in excess of 98{percent} of theoretical are readily obtained when processing at 1450{degree}C. TiC and Ni{sub 3}Al are the only phases detected in the densified materials. Ni{sub 3}Al ductility is retained after processing, leading to the possibility of ductile phase toughened TiC composites for elevated temperature applications (up to {approximately}1100{degree}C). {copyright} {ital 1997 Materials Research Society.}
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iron aluminide titanium carbide composites by pressureless Melt Infiltration microstructure and mechanical properties
Scripta Materialia, 1996Co-Authors: R. Subramanian, J H Schneibel, K B Alexander, K. P. PlucknettAbstract:In this investigation, processing of fully dense TiC-based cermets with iron aluminide (Fe-40 at. % Al) as a binder by pressureless Melt Infiltration has been clearly demonstrated. The carbide contents in these composites varied from 70 to 85 vol. %. Specimens with 30 vol. % intermetallic exhibited bend strengths of 1034 MPa, fracture toughness of 18 MPa{center_dot}m{sup 1/2} and a Rockwell (R{sub A}) hardness of 83.5. Further improvements in bend strengths may be possible by controlling the grain size and by modifications of the Fe40Al/TiC interface strengths.
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Iron aluminide-titanium carbide composites by pressureless Melt Infiltration — Microstructure and mechanical properties
Scripta Materialia, 1996Co-Authors: R. Subramanian, Joachim H. Schneibel, K B Alexander, K. P. PlucknettAbstract:In this investigation, processing of fully dense TiC-based cermets with iron aluminide (Fe-40 at. % Al) as a binder by pressureless Melt Infiltration has been clearly demonstrated. The carbide contents in these composites varied from 70 to 85 vol. %. Specimens with 30 vol. % intermetallic exhibited bend strengths of 1034 MPa, fracture toughness of 18 MPa{center_dot}m{sup 1/2} and a Rockwell (R{sub A}) hardness of 83.5. Further improvements in bend strengths may be possible by controlling the grain size and by modifications of the Fe40Al/TiC interface strengths.
Donald R. Behrendt - One of the best experts on this subject based on the ideXlab platform.
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reactive Melt Infiltration of silicon molybdenum alloys into microporous carbon preforms
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 1995Co-Authors: M. Singh, Donald R. BehrendtAbstract:Abstract Investigations on the reactive Melt Infiltration of silicon-1.7 and 3.2 at.% molybdenum alloys into microporous carbon preforms have been carried out by modeling, differential thermal analysis (DTA), and Melt Infiltration experiments. These results indicate that the pore volume fraction of the carbon perform is a very important parameter in determining the final composition of the reaction-formed silicon carbide and the secondary phases. Various undesirable Melt Infiltration results, e.g. choking-off, specimen cracking, silicon veins, and lake formation, and their correlation with inadequate preform properties are presented. The liquid silicon-carbon reaction exotherm temperatures are influenced by the pore and carbon particle size of the preform and the compositions of infiltrants. Room temperature flexural strength and fracture toughness of materials made by the silicon-3.2 at.% molybdenum alloy Infiltration of medium pore size preforms are also discussed.
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Reactive Melt Infiltration Of Silicon Into Porous Carbon
1994Co-Authors: Donald R. Behrendt, M. SinghAbstract:Report describes study of synthesis of silicon carbide and related ceramics by reactive Melt Infiltration of silicon and silicon/molybdenum alloys into porous carbon preforms. Reactive Melt Infiltration has potential for making components in nearly net shape, performed in less time and at lower temperature. Object of study to determine effect of initial pore volume fraction, pore size, and Infiltration material on quality of resultant product.
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Melt-Infiltration Process For SiC Ceramics And Composites
1994Co-Authors: Donald R. Behrendt, M. SinghAbstract:Reactive Melt Infiltration produces silicon carbide-based ceramics and composites faster and more economically than do such processes as chemical vapor Infiltration (CVI), reaction sintering, pressureless sintering, hot pressing, and hot isostatic pressing. Process yields dense, strong materials at relatively low cost. Silicon carbide ceramics and composites made by reactive Melt Infiltration used in combustor liners of jet engines and in nose cones and leading edges of high-speed aircraft and returning spacecraft. In energy industry, materials used in radiant-heater tubes, heat exchangers, heat recuperators, and turbine parts. Materials also well suited to demands of advanced automobile engines.
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reactive Melt Infiltration of silicon niobium alloys in microporous carbons
Journal of Materials Research, 1994Co-Authors: M. Singh, Donald R. BehrendtAbstract:Studies of the reactive Melt Infiltration of silicon-niobium alloys in microporous carbon preforms prepared by the pyrolysis of a polymer precursor have been carried out using modeling, Differential Thermal Analysis (DTA), and Melt Infiltration. Mercury porosimetry results indicate a very narrow pore size distribution with virtually all the porosity within the carbon preforms open to infiltrants. The morphology and amount of the residual phases (niobium disilicide and silicon) in the infiltrated material can be tailored according to requirements by careful control of the properties (pore size and pore volume) of the porous carbon preforms and alloy composition. The average room temperature four-point flexural strength of a reaction-formed silicon carbide material (made by the Infiltration of medium pore size carbon preform with Si - 5 at. % Nb alloy) is 290 +/- 40 MPa (42 +/- 6 ksi) and the fracture toughness is 3.7 +/- 0.3 MPa square root of m. The flexural strength decreases at high temperatures due to relaxation of residual thermal stresses and the presence of free silicon in the material.
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Studies on the reactive Melt Infiltration of silicon and silicon-molybdenum alloys in porous carbon
1992Co-Authors: M. Singh, Donald R. BehrendtAbstract:Investigations on the reactive Melt Infiltration of silicon and silicon-1.7 and 3.2 at percent molybdenum alloys into porous carbon preforms have been carried out by process modeling, differential thermal analysis (DTA) and Melt Infiltration experiments. These results indicate that the initial pore volume fraction of the porous carbon preform is a critical parameter in determining the final composition of the reaction-formed silicon carbide and other residual phases. The pore size of the carbon preform is very detrimental to the exotherm temperatures due to liquid silicon-carbon reactions encountered during the reactive Melt Infiltration process. A possible mechanism for the liquid silicon-porous (glassy) carbon reaction has been proposed. The composition and microstructure of the reaction-formed silicon carbide has been discussed in terms of carbon preform microstructures, Infiltration materials, and temperatures.