The Experts below are selected from a list of 119190 Experts worldwide ranked by ideXlab platform
Hanlin Liao - One of the best experts on this subject based on the ideXlab platform.
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effect of residual stresses on air plasma sprayed thermal barrier coatings
Surface & Coatings Technology, 2003Co-Authors: Nusair A Khan, Hanlin LiaoAbstract:Abstract Thermal barrier coating with a CoNiCrAlY bond coating and a 0.3 mm thick zirconia, (7% yttria stabilized) top coating were air plasma sprayed onto a Hastelloy-X nickel based super alloy substrate coupons. Substrate preparation is a key initial step in the production of quality thermal sprayed coatings. Grit blasting is usually used to roughen the substrate surface so that better adhesion of the coating to the substrate is achieved. The effects of different grit blasting variables on the substrate surface roughness were examined by using the Taguchi designed experimentation. The residual stress profiles were determined for a different set of conditions by hole drill method. The Anstis et al. model was modified for the determination of indent Toughness of the substrate and bond coat interface. The results showed that the combination of grit size with distance and pressure during the grit blasting were the most influential parameters. The adhesion of the coatings increases with increase of substrate roughness up to certain limits and then decreases. It was observed that the residual stresses have an impact over the adhesion of the coatings. The indentation Toughness results showed that with increase of substrate roughness there is an increase in interfacial Toughness due to high compressive stresses associated with high rough surfaces. Further, the final deposition temperature and heat treatment effect the residual stress profile and subsequently the interfacial Toughness of the coatings.
Tong Earn Tay - One of the best experts on this subject based on the ideXlab platform.
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Interlaminar fracture Toughness of hybrid woven carbon-Dyneema composites
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Y. Zhao, Miao Cao, W.p. Lum, Vincent B. C. Tan, Tong Earn TayAbstract:Abstract This study investigates the delamination behavior of carbon-Dyneema hybrid composites with different hybridization schemes. It is found that hybridization improves both mode I and mode II fracture Toughness of carbon-Dyneema interfaces. This is attributed to the large yarn size of Dyneema fibers, which results in an increase of the resin rich thickness at the interface between plies. The fracture surface with adjacent Dyneema fibers exhibits high surface roughness leading to higher fracture Toughness. Additionally, the thicker resin-rich interface promotes a cohesive-type failure within the resin rich zone, while fracture in the thinner carbon-carbon interface is dominated by adhesive-type failure. The mode II delamination of the carbon-Dyneema interface shows an increasing resistance curve, which may be attributed to friction between the rough delamination surfaces. The results demonstrate that hybridization with Dyneema could potentially be an effective toughening technique for thermoset carbon fiber composites.
Yuwei Wang - One of the best experts on this subject based on the ideXlab platform.
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interfacial properties and impact Toughness of methylphenylsilicone resin composites by chemically grafting poss and tetraethylenepentamine onto carbon fibers
Composites Part A-applied Science and Manufacturing, 2016Co-Authors: Yuwei Wang, Li Liu, Yudong HuangAbstract:Abstract Octaglycidyl polyhedral oligomeric silsesquioxane (gly-POSS) was successfully grafted on carbon fibers (CFs) surface to enhance interfacial properties and impact Toughness of CFs reinforced methylphenylsilicone resin (MPSR) composites. After gly-POSS modification, POSS grafted CF (CF-POSS) with many epoxy functional groups was modified with tetraethylenepentamine (TEPA) to further enhance the interfacial strength. Atomic force microscopy (AFM) images showed that POSS and TEPA were grafted onto CFs surface uniformly and the surface roughness enhanced obviously. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed the chemical bonding nature between CFs and POSS, as well as between POSS and TEPA. POSS and TEPA modification could increase the fiber polarity, wettability and surface energy significantly. The interlaminar shear strength (ILSS) and impact Toughness of composites showed a dramatic improvement, especially for grafting with POSS and further with TEPA (CF-POSS-TEPA). Additionally, the reinforcing and toughening mechanisms were also analyzed. Meanwhile, single fiber tensile strength (TS) had no decrease after modification.
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Improving the interfacial properties of carbon fiber-reinforced epoxy composites by grafting of branched polyethyleneimine on carbon fiber surface in supercritical methanol
Composites Science and Technology, 2015Co-Authors: Lichun Ma, Yuwei Wang, Linghui Meng, Guangshun Wu, Min Zhao, Chunhua Zhang, Yudong HuangAbstract:Abstract We report on a new application of branched polyethyleneimine as a coupling agent to functionalize carbon fibers in conventional and supercritical methods. The microstructure and mechanical properties of carbon fibers before and after modification were investigated. Polyethyleneimine could increase the polarity, wettability and roughness of the carbon fiber surface, and supercritical methanol was also able to improve the reaction efficiency. The interfacial shear strength and impact Toughness improved significantly when using the two methods, especially in supercritical methanol. Reinforcing and toughening mechanisms have also been discussed. Functionalization does not decrease fiber tensile strength.
Nusair A Khan - One of the best experts on this subject based on the ideXlab platform.
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effect of residual stresses on air plasma sprayed thermal barrier coatings
Surface & Coatings Technology, 2003Co-Authors: Nusair A Khan, Hanlin LiaoAbstract:Abstract Thermal barrier coating with a CoNiCrAlY bond coating and a 0.3 mm thick zirconia, (7% yttria stabilized) top coating were air plasma sprayed onto a Hastelloy-X nickel based super alloy substrate coupons. Substrate preparation is a key initial step in the production of quality thermal sprayed coatings. Grit blasting is usually used to roughen the substrate surface so that better adhesion of the coating to the substrate is achieved. The effects of different grit blasting variables on the substrate surface roughness were examined by using the Taguchi designed experimentation. The residual stress profiles were determined for a different set of conditions by hole drill method. The Anstis et al. model was modified for the determination of indent Toughness of the substrate and bond coat interface. The results showed that the combination of grit size with distance and pressure during the grit blasting were the most influential parameters. The adhesion of the coatings increases with increase of substrate roughness up to certain limits and then decreases. It was observed that the residual stresses have an impact over the adhesion of the coatings. The indentation Toughness results showed that with increase of substrate roughness there is an increase in interfacial Toughness due to high compressive stresses associated with high rough surfaces. Further, the final deposition temperature and heat treatment effect the residual stress profile and subsequently the interfacial Toughness of the coatings.
Yudong Huang - One of the best experts on this subject based on the ideXlab platform.
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interfacial properties and impact Toughness of methylphenylsilicone resin composites by chemically grafting poss and tetraethylenepentamine onto carbon fibers
Composites Part A-applied Science and Manufacturing, 2016Co-Authors: Yuwei Wang, Li Liu, Yudong HuangAbstract:Abstract Octaglycidyl polyhedral oligomeric silsesquioxane (gly-POSS) was successfully grafted on carbon fibers (CFs) surface to enhance interfacial properties and impact Toughness of CFs reinforced methylphenylsilicone resin (MPSR) composites. After gly-POSS modification, POSS grafted CF (CF-POSS) with many epoxy functional groups was modified with tetraethylenepentamine (TEPA) to further enhance the interfacial strength. Atomic force microscopy (AFM) images showed that POSS and TEPA were grafted onto CFs surface uniformly and the surface roughness enhanced obviously. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed the chemical bonding nature between CFs and POSS, as well as between POSS and TEPA. POSS and TEPA modification could increase the fiber polarity, wettability and surface energy significantly. The interlaminar shear strength (ILSS) and impact Toughness of composites showed a dramatic improvement, especially for grafting with POSS and further with TEPA (CF-POSS-TEPA). Additionally, the reinforcing and toughening mechanisms were also analyzed. Meanwhile, single fiber tensile strength (TS) had no decrease after modification.
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Improving the interfacial properties of carbon fiber-reinforced epoxy composites by grafting of branched polyethyleneimine on carbon fiber surface in supercritical methanol
Composites Science and Technology, 2015Co-Authors: Lichun Ma, Yuwei Wang, Linghui Meng, Guangshun Wu, Min Zhao, Chunhua Zhang, Yudong HuangAbstract:Abstract We report on a new application of branched polyethyleneimine as a coupling agent to functionalize carbon fibers in conventional and supercritical methods. The microstructure and mechanical properties of carbon fibers before and after modification were investigated. Polyethyleneimine could increase the polarity, wettability and roughness of the carbon fiber surface, and supercritical methanol was also able to improve the reaction efficiency. The interfacial shear strength and impact Toughness improved significantly when using the two methods, especially in supercritical methanol. Reinforcing and toughening mechanisms have also been discussed. Functionalization does not decrease fiber tensile strength.
