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Yongchwang Chen - One of the best experts on this subject based on the ideXlab platform.

  • evolution of the microstructure and tribological performance of ti 6al 4v cladding with tin powder
    Materials & Design, 2012
    Co-Authors: Yongchwang Chen
    Abstract:

    Abstract Titanium nitrides (TiNs) powder was used as a material to resist wear; it was then clad onto a Ti–6Al–4V substrate by gas tungsten arc welding (GTAW). During the cladding process, the TiN x Reinforcing Phase was formed in situ within the clad layer. Since the TiN x Reinforcing Phase exists within the clad layer, the hardness of the clad layer is double that of the substrate. Wear test results reveal that the wear resistance of TiN clad layer is up to ten times more resistant than the Ti–6Al–4V substrate. From the worn surface analysis, the primary wear mechanism of the Ti–6Al–4V specimen exhibited oxidation wear combined with adhesive wear, and the TiN clad layer specimen exhibited abrasive wear. This investigation also discusses the mechanism for forming the clad layer microstructure. During solidification of the clad layer, the motion of the liquid–solid interface caused the oval TiN x Phase to cluster, producing a dendritic appearance.

Q. Chen - One of the best experts on this subject based on the ideXlab platform.

  • A computational study of the improvement in wear resistance of a pseudoelastic TiNi matrix composite achieved by adding TiN nanoparticles
    Smart Materials and Structures, 2007
    Co-Authors: Q. Chen
    Abstract:

    It has been demonstrated that a pseudoelastic TiNi matrix composite exhibits high resistance to wear, which benefits from the combination of a Reinforcing Phase and a flexible and wear-resistant matrix. The former mainly withstands the wearing force and the latter acts as a binder to retain the Reinforcing Phase, accommodate deformation and absorb impact energy. Due to its pseudoelasticity and high wear resistance, the TiNi matrix is markedly superior to many conventional matrix materials. The performance of the TiNi matrix can be further improved by embedding a small amount of hard nanoparticles in it. The nanoparticles effectively strengthen the matrix but degrade its pseudoelasticity. There exists an optimal volume fraction of nanoparticles, above which the effect of nanoparticles becomes negative. In order to better understand the role of the nanoparticles in improving the wear resistance of the composite and to maximize the benefit from the nanoparticles, a computational study was conducted using a dynamic simulation technique. It was demonstrated that a small amount of nanoparticles could effectively strengthen the matrix without much pseudoelasticity being lost. However, too many nanoparticles negatively influence the pseudoelasticity and the interfacial bond strength, leading to a decrease in the wear resistance.

  • Computer simulation of solid-particle erosion of composite materials
    Wear, 2003
    Co-Authors: Q. Chen
    Abstract:

    Abstract Solid-particle erosion is a complex surface damage process, strongly affected by mechanical and metallurgical factors. In this study, the surface damage of composite materials caused by solid-particle erosion was simulated using a dynamic computational model based on Newton’s law of motion. In this model, a material system is discretized and mapped onto a discrete lattice. Each lattice site represents a small volume of the target material or the solid particle. During erosion, a lattice site may move under the influence of the impingement between ejected solid particles and the target material as well as the interaction between the site and its adjacent sites. The site–site interaction is a function of mechanical properties of the materials, including the elastic modulus, the yield strength, work hardening and the fracture strain. A bond connecting two adjacent sites is broken when its strain exceeds the fracture strain. A site or a cluster of sites can be worn away if all bonds connecting the site or the cluster to its adjacent sites are broken. Effects of the volume fraction of Reinforcing Phase and the bonding strength of the Reinforcing Phase/matrix interface on the erosion behavior of a composite material were investigated. In addition, effects of the impact velocity, the solid-particle size and the size ratio of the solid particle to the Reinforcing Phase on erosion of the composite were also studied. It was demonstrated that the model was effective for investigating the mechanism responsible for erosion of materials and helpful for establishing the relationship between the microstructure of a material and its wear behavior.

Lisbeth Grøndahl - One of the best experts on this subject based on the ideXlab platform.

  • Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) composite biomaterials for bone tissue regeneration: in vitro performance assessed by osteoblast proliferation, osteoclast adhesion and resorption, and macrophage proinflammatory response.
    Journal of biomedical materials research. Part A, 2007
    Co-Authors: Simon M. Cool, Benjamin Kenny, Victor Nurcombe, Matt Trau, A. I. Cassady, Lisbeth Grøndahl
    Abstract:

    The efficacy of composite materials for bone tissue engineering is dependent on the materials' ability to support bone regeneration whilst inducing a minimal inflammatory response. In this study we examined the in vitro ostegenic and inflammatory properties of poly(3-hydroxybutyrate-co-3-valerate) (PHBV) with various calcium phosphate-Reinforcing Phases: nano-sized hydroxyapatite (HA); submicron-sized calcined hydroxyapatite (cHA); and submicron-sized beta-tricalcium phosphate (beta-TCP), using bioassavs of cultured osteoblasts, osteoclasts, and macrophages. Our study showed that the addition of a nano-sized Reinforcing Phase to PHBV, whilst improving osteogenic properties, also reduces the proinflammatory response. Proinflammatory responses of RAW264.7/ELM4-eGFP macrophages to PHBV were shown to be markedly reduced by the introduction of a Reinforcing Phase, with HA/PHBV composites having the lowest inflammatory response. Osteoclasts, whilst able to attach to all the materials, failed to form functional actin rings or resorption pits on any of the materials under investigation. Cultures of osteoblasts (MC3T3-E1) readily attached and mineralised on all the materials, with HA/PHBV inducing the highest levels of mineralization. The improved biological performance of HA/PHBV composites when compared with cHA/PHBV and beta-TCP/PHBV composites is most likely a result of the nano-sized Reinforcing Phase of HA/PHBV and the greater surface presentation of mineral in these composites. Our results provide a new strategy for improving the suitability of PHBV-based materials for bone tissue regeneration. (C) 2007 Wiley Periodicals, Inc.

  • Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) composite biomaterials for bone tissue regeneration:In vitro performance assessed by osteoblast proliferation, osteoclast adhesion and resorption, and macrophage proinflammatory response
    Journal of Biomedical Materials Research Part A, 2007
    Co-Authors: Simon M. Cool, Benjamin Kenny, Victor Nurcombe, Matt Trau, A. I. Cassady, Lisbeth Grøndahl
    Abstract:

    The efficacy of composite materials for bone tissue engineering is dependent on the materials' ability to support bone regeneration whilst inducing a minimal inflammatory response. In this study we examined the in vitro osteogenic and inflammatory properties of poly(3-hydroxybutyrate-co-3-valerate) (PHBV) with various calcium phosphate-Reinforcing Phases: nano-sized hydroxyapatite (HA); submicron-sized calcined hydroxyapatite (cHA); and submicron-sized β-tricalcium phosphate (β-TCP), using bioassays of cultured osteoblasts, osteoclasts, and macrophages. Our study showed that the addition of a nano-sized Reinforcing Phase to PHBV, whilst improving osteogenic properties, also reduces the proinflammatory response. Proinflammatory responses of RAW264.7/ELAM-eGFP macrophages to PHBV were shown to be markedly reduced by the introduction of a Reinforcing Phase, with HA/PHBV composites having the lowest inflammatory response. Osteoclasts, whilst able to attach to all the materials, failed to form functional actin rings or resorption pits on any of the materials under investigation. Cultures of osteoblasts (MC3T3-E1) readily attached and mineralised on all the materials, with HA/PHBV inducing the highest levels of mineralization. The improved biological performance of HA/PHBV composites when compared with cHA/PHBV and β-TCP/PHBV composites is most likely a result of the nano-sized Reinforcing Phase of HA/PHBV and the greater surface presentation of mineral in these composites. Our results provide a new strategy for improving the suitability of PHBV-based materials for bone tissue regeneration.Griffith Health FacultyNo Full Tex

A.e. Karantzalis - One of the best experts on this subject based on the ideXlab platform.

  • Microstructure and Corrosion Performance of Aluminium Matrix Composites Reinforced with Refractory High-Entropy Alloy Particulates
    Applied Sciences, 2021
    Co-Authors: Elias Ananiadis, Konstantinos T. Argyris, Theodore E. Matikas, A.k. Sfikas, A.e. Karantzalis
    Abstract:

    Novel aluminium matrix composites reinforced by MoTaNbVW refractory high-entropy alloy (HEA) particulates have been fabricated by powder metallurgy. The microstructure of the produced composites has been studied and the corrosion behaviour assessed in 3.5% NaCl solution. The composites exhibited low porosity, good homogeneity, few defects, and good distribution of the Reinforcing Phase in the Al matrix. No secondary intermetallic Phases have been formed while the interface between matrix/reinforcement showed good bonding with no signs of reactivity. Increasing the volume of the Reinforcing Phase leads to increased hardness values. Al-HEA composites exhibited susceptibility to localised forms of corrosion in 3.5% NaCl solution. The microstructure has been analysed and corrosion mechanisms have been formulated.

  • al mosi2 composite materials analysis of microstructure sliding wear solid particle erosion and aqueous corrosion
    Journal of Materials Engineering and Performance, 2016
    Co-Authors: V Gousia, A Tsioukis, A Lekatou, A.e. Karantzalis
    Abstract:

    In this effort, AMCs reinforced with new intermetallic Phases, were produced through casting and compared as far as their microstructure, sliding wear, solid particle erosion, and aqueous corrosion response. Casting was selected as a production method based on the concept: (a) ease-to-handle and low cost production route and (b) optimum homogeneity of the Reinforcing Phase distribution. The MoSi2 Phase was produced through vacuum arc melting and the resulting drops were milled for 30 h to produce fine powder, the characteristics of which were ascertained through SEM-EDS and XRD analysis. MoSi2 was used as precursor source for the final Reinforcing Phase. The powder material was incorporated in molten Al1050 alloy to additions of 2, 5 and 10 vol.% respectively. Extensive reactivity between the molten Al and the MoSi2 particles was observed, leading to the formation of new Reinforcing Phases mainly of the Al-Mo system. In all cases, a uniform particle distribution was observed, mainly characterized by isolated intermetallic Phases and few intermetallic Phase clusters. Sliding wear showed a beneficial action of the Reinforcing Phase on the wear of the composites. Surface oxidation, plastic deformation, crack formation, and debris abrasive action were the main degradation features. The results of solid particle erosion showed that the mechanism is different as the impact angle and the vol.% change. Regarding the corrosion, the analysis revealed localized corrosion effects. The composite behavior was not altered significantly compared to that of the monolithic matrix.

Wei-liang Liu - One of the best experts on this subject based on the ideXlab platform.

  • Simultaneously Reinforcing and toughening plasticized starch film via regenerated cellulose as Reinforcing Phase
    Journal of Polymer Research, 2016
    Co-Authors: Xiaoxia Cai, Yuansong Zhang, Qinze Liu, Wei-liang Liu
    Abstract:

    Using regenerated cellulose (RC) as Reinforcing Phase, a series of glycerol plasticized corn starch (PCS) films were developed via a simple casting pathway. Wide angle X-ray diffraction (WAXD) showed that compared to cellulose crystallites (CC), the RC, dissolved in NaOH/urea aqueous solution and then regenerated by water, exhibited a significant decrease in intermolecular hydrogen bonding. Scanning electron microscopy (SEM) confirmed that compared to CC, a better dispersion of RC in PCS matrix was achieved, and higher tensile strength and elongation at break was obtained. More important, an unusual simultaneous film Reinforcing and toughening phenomenon occurred after the addition of RC. Even the weight ratio of RC was up to 20 %, the elongation at break was still higher than that of pure PCS film. A schematic was presented to demonstrate the dispersion features of RC in glycerol plasticized starch film and illustrate this unique mechanical behavior.