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Volume fraction
About: Volume fraction is a research topic. Over the lifetime, 16312 publications have been published within this topic receiving 374181 citations.
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TL;DR: In this paper, a technique for preparing model Functionally Gradient Materials (FGM) using polyester resin and cenospheres is developed, where the cenosphere volume fraction in the polyester matrix is continuously varied through a buoyancy assisted casting process.
Abstract: A technique for preparing model Functionally Gradient Materials (FGM) using polyester resin and cenospheres is developed. The cenosphere volume fraction in the polyester matrix is continuously varied through a buoyancy assisted casting process. FGMs having cenosphere volume fraction varying from 0 to 0.45 over a length of 250 mm are prepared. The overall properties of the FGM are varied by adding plasticizer to the polyester matrix. The physical, elastic and fracture properties of the prepared FGMs are evaluated as a function of location to generate the property profiles. The results of the material characterization indicate that, the quasi-static and dynamic modulus of the material increases and the material density decreases in the direction of increasing cenosphere volume fraction. The quasi-static fracture toughness increases up to a certain volume fraction of cenospheres and then decreases. Fractographic analyses of the fractured specimens indicate a change in the fracture mechanism as the cenosphere volume fraction increases. Estimate of the composite modulus using the Halpin-Tsai model with porosity correction matches closely with the test results.
118 citations
TL;DR: In this article, two laser surface engineering techniques, Laser Cladding and Laser Melt Injection (LMI), were used to prepare three different metal matrix composite layers with a thickness of about 1 mm and approximately 25% volume fraction of ceramic particles.
Abstract: Two laser surface engineering techniques, Laser Cladding and Laser Melt Injection (LMI), were used to prepare three different metal matrix composite layers with a thickness of about 1 mm and approximately 25‐30% volume fraction of ceramic particles. SiC/Al‐8Si, WC/Ti‐6Al‐4Vand TiB2/Ti‐6Al‐4V layers were prepared by a Laser Melt Injection process, whereby additional material in the form of ceramic particles is injected into the molten substrate. As a result, a microstructure characterized by hard ceramic particles distributed in a metal matrix with very strong bonding is formed in the surface layer of the treated metal. A TiB/Ti‐6Al‐4V metal matrix composite layer was produced on Ti‐6Al‐4V substrates by conventional laser cladding. A mixture of TiB2/Ti powders has been used as a precursor to obtain two microstructurally distinct layers, namely eutectic and primary TiB particles dispersed in the Ti‐6Al‐4V matrix. Sliding wear properties of these metal matrix composites layers were studied at boundary lubrication conditions and compared with the wear of the substrate materials. The observed wear mechanisms are summarized and related to detailed microstructural observations. The layers have been found to show excellent interfacial bonding, coupled with dramatically improved tribological properties expressed through a relative wear resistance value ranging from 30 to 1500. D 2004 Elsevier B.V. All rights reserved.
118 citations
TL;DR: The microstructural changes produced by large (38 to 53 μm), single-crystal ZrO2 inclusions within an Al2O3 powder matrix were detailed as a function of constrained densification as discussed by the authors.
Abstract: The microstructural changes produced by large (38 to 53 μm), single-crystal ZrO2 inclusions (0, 0.09, 0.30 volume fractions, based on solid volume) within an Al2O3 powder matrix were detailed as a function of constrained densification. Composite powder compacts were produced by pressure filtration for conditions where the Al2O3 slurry was either flocced or dispersed. For both conditions, the ZrO2 inclusions constrained densification. Microstructural observations for all composites revealed (1) the presence of cracks with large opening displacements between inclusions and (2) large density variations within the matrix. The cracks were most frequent at high volume fraction of inclusions in composites produced from flocced slurries and apparently originated during specimen preparation. Their large opening displacment was a result of matrix densification. Fewer cracks were observed in composites produced from dispersed slurries. Instead, these microstructures were dominated by large variations in matrix density, viz., dense regions surrounding low-density regions, not consitent with the initial packing density of the matrix powder. The denser regions were formed early in the densification schedule. The lower-density regions eventually developed into regions containing large, elongated voids as the Al2O3 matrix grains became larger with heat-treatment time. This pore enlargement process was shown to result from the disappearance of necks between originally sintered grains and appeared similar to the thermodynamic instability observed in thin films and constrained fibers.
118 citations
TL;DR: A stacking and folding method is used to generate aligned graphene/polycarbonate composites with as many as 320 parallel layers spanning 0.032 to 0.11 millimeters in thickness that significantly increases the effective elastic modulus and strength at exceptionally low volume fractions of only 0.082%.
Abstract: Two-dimensional (2D) materials can uniquely span the physical dimensions of a surrounding composite matrix in the limit of maximum reinforcement. However, the alignment and assembly of continuous 2D components at high volume fraction remain challenging. We use a stacking and folding method to generate aligned graphene/polycarbonate composites with as many as 320 parallel layers spanning 0.032 to 0.11 millimeters in thickness that significantly increases the effective elastic modulus and strength at exceptionally low volume fractions of only 0.082%. An analogous transverse shear scrolling method generates Archimedean spiral fibers that demonstrate exotic, telescoping elongation at break of 110%, or 30 times greater than Kevlar. Both composites retain anisotropic electrical conduction along the graphene planar axis and transparency. These composites promise substantial mechanical reinforcement, electrical, and optical properties at highly reduced volume fraction.
118 citations
TL;DR: The tensile and Izod impact strength of polycarbonate (PC) based polyethylene (PE) and polystyrene (PS) blends has been examined in this paper.
Abstract: The tensile and Izod impact strength of polycarbonate (PC) based polyethylene (PE) and polystyrene (PS) blends has been examined. The tensile strength can best be described as being proportional to an exponential function of the volume fraction of PE and the first power of volume fraction of PS. The variation of Izod impact strength with composition also differs considerably for the two blends, a small amount of PS causing a marked drop in impact strength. The impact strength of the PE/PC blend is related to the area under the tensile stress-strain curve, whereas for PS/PC blends no correspondence is found. The variation in properties is related to the composition, morphology, interfacial adhesion at the phase boundary and failure surfaces of the various blends.
118 citations