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D D L Chung - One of the best experts on this subject based on the ideXlab platform.

  • Low-volume-fraction particulate preforms for making Metal-matrix composites by Liquid Metal Infiltration
    Journal of Materials Science, 1998
    Co-Authors: Yunsheng Xu, D D L Chung
    Abstract:

    A preform technology for making particulate Metal-matrix composites with a low particulate volume fraction (as low as 18%) by Liquid Metal Infiltration is provided. This technology used a non-combustible reinforcement (SiC) as the primary particulate and combustible particles (carbon) as the secondary particulate in the preform. The secondary particulate was removed from the preform by oxidation prior to Liquid Metal Infiltration.

  • Silicon-aluminium network composites fabricated by Liquid Metal Infiltration
    Journal of Materials Science, 1994
    Co-Authors: Yuyong Chen, D D L Chung
    Abstract:

    This paper provides a new method for fabricating interpenetrating silicon-aluminium network Metal-matrix composites. This method involves the Infiltration of an aluminium-silicon alloy (Al-12Si-1Mg or Al-30Si-1Mg) Liquid into a silicon particle (50 vol %) preform. The silicon particles were partially dissolved by the Liquid alloy and, together with silicon contributed by the original Al-Si-Mg matrix, resulted in an Si network after solidification. The network composites were Metallurgically sound, with no porosity, and exhibited a thermal expansion coefficient down to 7.7×10^−6 °C^−1 at 50–100 °C, compressive strength up to 580 MPa, tensile strength up to 160 MPa and Vickers hardness up to 390.

  • phase distribution and associated mechanical property distribution in silicon carbide particle reinforced aluminium fabricated by Liquid Metal Infiltration
    Journal of Materials Science, 1994
    Co-Authors: Shy Wen Lai, D D L Chung
    Abstract:

    The reaction between silicon carbide and aluminium to form silicon and Al4C3 in SiC particle-reinforced aluminium fabricated by Liquid aluminium Infiltration was most severe near the original interface between Liquid aluminium and the SiC preform. This resulted in the highest concentration of Al4C3 and the lowest concentrations of silicon and SiC in the part of the composite near this interface. In particular, the silicon concentration was highest in the bottom centre of the composite when Infiltration occurred from the top, because silicon diffused toward the surrounding aluminium melt before solidification. These non-uniform phase distributions, as measured by X-ray diffraction and differential scanning calorimetry, did not cause any non-uniform shear strength distribution. However, excessive reaction between SiC and aluminium, as observed for an Infiltration (=mould=Liquid Metal) temperature of 780° C, caused the tensile strength to decrease. In the case where a steel mould was used during Infiltration at 780° C, iron-containing precipitates, such as ternary Al-Fe-Si, were observed in the part of the composite within 5 mm from the above-mentioned interface; their formation was related to the silicon out-diffusion in the form of Liquid Al-Si; they caused the shear strength to be lower in this part of the composite; larger such precipitates (up to 100 μm) were observed in the excess aluminium adjacent to the cast composite. For pure aluminium as the infiltrating Metal, the optimum Infiltration temperature for the highest tensile strength was 700° C. An Infiltration temperature of 670° C resulted in incomplete Infiltration, which was more severe when a steel mould rather than a graphite mould was used because of the higher thermal conductivity of the former.

  • Fabrication of particulate aluminium-matrix composites by Liquid Metal Infiltration
    Journal of Materials Science, 1994
    Co-Authors: Shy Wen Lai, D D L Chung
    Abstract:

    Aluminium-matrix composites were fabricated by Liquid Metal Infiltration\nof porous particulate\n\nreinforcement preforms, using AIN, SiC and AI203 as the particles.\nThe quality of the\n\ncomposites depended on the preform fabrication technology. In this\nwork, this technology\n\nwas developed for high-volume fraction (up to 75%) particulate preforms,\nwhich are more\n\nsensitive to the preform fabrication process than lower volume fraction\nwhisker/fibre preforms\n\nas their porosity and pore size are much lower. The technology developed\nused an acid\n\nphosphate binder (with P/AI molar ratio=23) in the amount of 0.1 wt%\nof the preform, in\n\ncontrast to the much larger binder amount used for whisker preforms.\nThe preforms were\n\nmade by filtration of a slurry consisting of the reinforcement particles,\nthe binder and carrier\n\n(preferably acetone), and subsequent baking (preferably at 200 ~ for\nthe purpose of drying.\n\nBaking in air at 500~ instead of 200~ caused the AIN preforms to oxidize,\nthereby\n\ndecreasing the thermal conductivity of the resulting AI/AIN composites.\nThe reinforcementbinder\n\nreactivity was larger for AIN than SiC, but this reactivity did not\naffect the composite\n\nproperties due to the small binder amount used. The AI/AIN composites\nwere superior to the\n\nAI/SiC composites in the thermal conductivity and tensile ductility.\nThe AI/AI203 composites\n\nwere the poorest due to AI203 particle clustering.

J.m. Molina - One of the best experts on this subject based on the ideXlab platform.

  • On the triple line in Infiltration of Liquid Metals into porous preforms
    Scripta Materialia, 2010
    Co-Authors: J.m. Molina, Javier Narciso, E Louis
    Abstract:

    Two questions of current interest are addressed in this paper: (i) Are contact angles measured by means of the sessile drop technique of any help to understand Liquid Metal Infiltration into solid porous preforms? (ii) To what extent are contact angles derived from either the capillary law or drainage curves valid? These questions have neither simple nor unique answers, as Infiltration may occur under very different scenarios, i.e., non-reactive and reactive Infiltration, both spontaneous and forced. However, while the use of the simplest version of the capillary law relies upon the questionable slug-flow hypothesis, analysing drainage curves by means of the Brooks and Corey model seems justified only for particular distributions of pore sizes such as a power law. However, experimental studies indicate that threshold pressures, and therefore contact angles, derived from those two methods are not very different.

  • High-temperature wettability of aluminum nitride during Liquid Metal Infiltration
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008
    Co-Authors: M. Kida, M. Bahraini, J.m. Molina, Ludger Weber, Andreas Mortensen
    Abstract:

    The high-temperature wettability of AlN particle preforms with pure molten Cu, Al and Ph is quantified by means of drainage curves measured during pressure Infiltration. By integrating the drainage curves obtained in this study, the work of immersion for each system can be estimated, allowing in turn to deduce an apparent contact angle for wetting of AlN by these Metals. The influence of system nature and temperature on the apparent contact angle are studied and discussed by comparison with literature values measured using the sessile drop method. (C) 2008 Elsevier B.V. All rights reserved.

  • Liquid Metal Infiltration into ceramic particle compacts chemically and morphologically heterogeneous
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008
    Co-Authors: E Pinero, J.m. Molina, Javier Narciso, E Louis
    Abstract:

    The threshold pressure P-0 for Infiltration of Al-12 wt.% Si alloy into compacts of mixtures of alumina and silicon carbide particles having largely different size is investigated. The results are in line with those recently derived from Infiltrations of Al into bimodal SiC compacts, namely, P-0 remains almost constant for fractions of coarse particles below that which gives the maximum particle volume fraction, decreasing there onwards down to the value corresponding to coarse particles. The experimental data for P-0 can be reasonably fitted by generalizing an approach, recently developed for SiC bimodal compacts, which gives P-0 in terms of the mixture specific surface area calculated by means of the linear rule of mixtures. (C) 2008 Elsevier B.V. All rights reserved.

  • Measuring and tailoring capillary forces during Liquid Metal Infiltration
    Current Opinion in Solid State & Materials Science, 2005
    Co-Authors: M. Bahraini, J.m. Molina, Ludger Weber, M. Kida, Javier Narciso, Andreas Mortensen
    Abstract:

    A new technique is proposed for the direct measurement of capillary forces in systems of relevance to the Infiltration processing of Metal matrix composites. Capable of handling melt temperatures up to 1500 K and Infiltration pressures up to 20 MPa, the technique is essentially a high-temperature analogue of mercury porosimetry. Its accuracy is demonstrated by comparison with other techniques and its use is illustrated with the Infiltration of diamond particle preforms by Al and Al-Si alloys at 973 K. (c) 2006 Elsevier Ltd. All rights reserved.

  • Liquid Metal Infiltration into ceramic particle preforms with bimodal size distributions
    Current Opinion in Solid State & Materials Science, 2005
    Co-Authors: J.m. Molina, E Pinero, J Narciso, C Garciacordovilla, E Louis
    Abstract:

    Abstract The work carried out during the last years on pressure Infiltration of Liquid Metals into ceramic compacts made of bimodal mixtures of particles is reviewed. The use of bimodal mixtures of particles largely different in size, allows obtaining preforms, and thus, composites, with particle volume fractions V p high enough to be used as supports in electronic packaging. The experimental results for the particle volume fraction are rationalized using a simple model that assumes that small particles can be easily accommodated in the free space left by large particles. Threshold pressure for Infiltration P 0 seems to be mainly controlled by the local compactness of fine particles. The experimental results for P 0 can be fitted using the particle surface area per unit volume given by the linear rule of mixtures. The intrinsic permeability of the preforms, evaluated by means of pressureless Infiltration of an organic Liquid, can be rationalized in terms of models used in soil science. Thermal properties of the composites are also briefly discussed. The coefficient of thermal expansion calculated over a wide temperature range decreases linearly with the particle volume fraction, indicating that the key parameter is V p , while other characteristics of the composite are irrelevant or play a minor role. The experimental results for the thermal conductivity can be accounted for by Hasselman–Johnson formula, using, as above, the particle surface area per unit volume given by the linear mixture rule.

Yi Zeng - One of the best experts on this subject based on the ideXlab platform.

  • high temperature corrosion of carbon carbon composites in zr ti melts during Liquid Metal Infiltration
    Corrosion Science, 2015
    Co-Authors: Yi Zeng, Xiang Xiong, Dini Wang, Zhaoke Chen, Wei Sun, Yalei Wang, Ping Xiao
    Abstract:

    Abstract The carbon/carbon composites with Zr–Ti–C were prepared by Liquid Metal Infiltration (LMI) process. The chemical corrosion and thermal stress damage of carbon matrices in Zr–Ti melts were investigated. A corrosion mechanism and a method of rehabilitating defective materials were proposed. The results indicated that the internal carbon matrices of composites were not corroded by the Zr–Ti melts and their vapours. However, the superficial matrices contacting the melts were severely consumed. In addition, the release of thermal stress produced the defects. The flexural strength of the samples after LMI could be improved via a new deposition of pyrocarbon in the defects.

  • High temperature corrosion of carbon/carbon composites in Zr–Ti melts during Liquid Metal Infiltration
    Corrosion Science, 2015
    Co-Authors: Yi Zeng, Xiang Xiong, Dini Wang, Zhaoke Chen, Wei Sun, Yalei Wang, Ping Xiao
    Abstract:

    Abstract The carbon/carbon composites with Zr–Ti–C were prepared by Liquid Metal Infiltration (LMI) process. The chemical corrosion and thermal stress damage of carbon matrices in Zr–Ti melts were investigated. A corrosion mechanism and a method of rehabilitating defective materials were proposed. The results indicated that the internal carbon matrices of composites were not corroded by the Zr–Ti melts and their vapours. However, the superficial matrices contacting the melts were severely consumed. In addition, the release of thermal stress produced the defects. The flexural strength of the samples after LMI could be improved via a new deposition of pyrocarbon in the defects.

  • Infiltration mechanism and factors influencing carbon carbon zr ti c composites prepared by Liquid Metal Infiltration
    Journal of Materials Processing Technology, 2014
    Co-Authors: Yi Zeng, Xiang Xiong, Dini Wang
    Abstract:

    Abstract The effects of fibre architecture, reaction temperature and holding time on the Infiltration performance of carbon/carbon (C/C)–Zr–Ti–C composites prepared by Liquid Metal Infiltration were investigated. The results indicated that samples with a chopped-web needled preform and low initial density had a high final density. Increasing the reaction temperatures resulted in a decrease of the final density of samples. Additionally, increasing the initial holding time appeared to obviously result in a high final density, but its effectiveness was not obvious in later observations. An analysis of the Infiltration kinetics and mechanisms indicated that the diffusivity of carbon in the carbide, the open-pore sizes and their distribution in C/C composites were the essential characteristics that controlled the height of infiltrating melts.

  • Infiltration mechanism and factors influencing carbon/carbon–Zr–Ti–C composites prepared by Liquid Metal Infiltration
    Journal of Materials Processing Technology, 2014
    Co-Authors: Yi Zeng, Xiang Xiong, Dini Wang
    Abstract:

    Abstract The effects of fibre architecture, reaction temperature and holding time on the Infiltration performance of carbon/carbon (C/C)–Zr–Ti–C composites prepared by Liquid Metal Infiltration were investigated. The results indicated that samples with a chopped-web needled preform and low initial density had a high final density. Increasing the reaction temperatures resulted in a decrease of the final density of samples. Additionally, increasing the initial holding time appeared to obviously result in a high final density, but its effectiveness was not obvious in later observations. An analysis of the Infiltration kinetics and mechanisms indicated that the diffusivity of carbon in the carbide, the open-pore sizes and their distribution in C/C composites were the essential characteristics that controlled the height of infiltrating melts.

Umit Cocen - One of the best experts on this subject based on the ideXlab platform.

  • detrimental effect of particle sol gel coating on the corrosion behavior of a380 sic composite
    Corrosion Science, 2009
    Co-Authors: Burak Dikici, C. Tekmen, O. Yigit, Mehmet Gavgali, Umit Cocen
    Abstract:

    Abstract In this study, the corrosion susceptibility of aluminum matrix composites reinforced with artificially oxidized SiO 2 and sol–gel Fe/TiO 2 coated silicon carbide particles (SiC p ) has been investigated. Corrosion behavior of the composites, fabricated by the Liquid Metal Infiltration technique, was established in chloride containing alkaline environments by cyclic polarization (CP) and electrochemical impedance spectroscopy (EIS) techniques. It has been found that, sol–gel coating of SiC particles with Fe/TiO 2 has a detrimental effect on the corrosion characteristics of A380–SiC Metal matrix composite.

  • Detrimental effect of particle sol–gel coating on the corrosion behavior of A380–SiC composite
    Corrosion Science, 2009
    Co-Authors: Burak Dikici, C. Tekmen, O. Yigit, Mehmet Gavgali, Umit Cocen
    Abstract:

    Abstract In this study, the corrosion susceptibility of aluminum matrix composites reinforced with artificially oxidized SiO 2 and sol–gel Fe/TiO 2 coated silicon carbide particles (SiC p ) has been investigated. Corrosion behavior of the composites, fabricated by the Liquid Metal Infiltration technique, was established in chloride containing alkaline environments by cyclic polarization (CP) and electrochemical impedance spectroscopy (EIS) techniques. It has been found that, sol–gel coating of SiC particles with Fe/TiO 2 has a detrimental effect on the corrosion characteristics of A380–SiC Metal matrix composite.

Marie Salles - One of the best experts on this subject based on the ideXlab platform.

  • thermodynamic of Liquid Metal Infiltration in tic sic or sic porous compacts
    Journal of Alloys and Compounds, 2019
    Co-Authors: Jérôme Roger, Marie Salles
    Abstract:

    Abstract This work is the study of the reactivity during the capillary Infiltration of Liquid silicon or Si–Ti molten alloys in SiC or SiC + TiC compacts to form TiSi2/SiC composites. The main aim was to identify the thermodynamic and kinetic limitations of this process. Preliminary thermodynamic analyses of the equilibria in the Ti–Si–C system were performed to select the compositions of the Liquid and the operating temperatures. Three cases were chosen: 1) Infiltration of molten TiSi2 in pure SiC compacts at 1550 °C, 2) reactive Infiltration of pure Liquid silicon in SiC + TiC compacts at 1450 °C, and 3) reactive Infiltration of the molten eutectic Ti0.16Si0.84 alloy in SiC + TiC compacts at 1380 °C. The compacts were prepared from mixtures of micronic SiC (α or β polytypes) and TiC powders. The compositions of the powder mixtures were calculated to fill totally the porosity of the compacts of about 50% or with an excess of TiC. The heat treatments of the pellets at 1380, 1450 and 1550 °C were performed with a holding duration of 1 h in high vacuum. Experimental results evidenced that the interactions between the Liquid and the powders are complex. The obtained materials differ more or less from the expected composites that are generally not dense and contain variable quantities of free silicon. It is found that these experimental results can be explained by advanced thermodynamic calculations. This work proves that the activity gradients play a determining role during the Infiltration process by initiating the dissolution and the diffusion of atoms in the Liquids.

  • Thermodynamic of Liquid Metal Infiltration in TiC–SiC or SiC porous compacts
    Journal of Alloys and Compounds, 2019
    Co-Authors: Jérôme Roger, Marie Salles
    Abstract:

    Abstract This work is the study of the reactivity during the capillary Infiltration of Liquid silicon or Si–Ti molten alloys in SiC or SiC + TiC compacts to form TiSi2/SiC composites. The main aim was to identify the thermodynamic and kinetic limitations of this process. Preliminary thermodynamic analyses of the equilibria in the Ti–Si–C system were performed to select the compositions of the Liquid and the operating temperatures. Three cases were chosen: 1) Infiltration of molten TiSi2 in pure SiC compacts at 1550 °C, 2) reactive Infiltration of pure Liquid silicon in SiC + TiC compacts at 1450 °C, and 3) reactive Infiltration of the molten eutectic Ti0.16Si0.84 alloy in SiC + TiC compacts at 1380 °C. The compacts were prepared from mixtures of micronic SiC (α or β polytypes) and TiC powders. The compositions of the powder mixtures were calculated to fill totally the porosity of the compacts of about 50% or with an excess of TiC. The heat treatments of the pellets at 1380, 1450 and 1550 °C were performed with a holding duration of 1 h in high vacuum. Experimental results evidenced that the interactions between the Liquid and the powders are complex. The obtained materials differ more or less from the expected composites that are generally not dense and contain variable quantities of free silicon. It is found that these experimental results can be explained by advanced thermodynamic calculations. This work proves that the activity gradients play a determining role during the Infiltration process by initiating the dissolution and the diffusion of atoms in the Liquids.