scholarly journals A Preliminary Investigation of Ductility-Enhancement Mechanism through In Situ Nanofibrillation in Thermoplastic Matrix Composites

2013 ◽  
Vol 2013 ◽  
pp. 1-9
Author(s):  
Bhaskar Patham ◽  
M. P. Poornendu Thejaswini
Keyword(s):  
Plastic Deformation ◽  
Surface Energy ◽  
Preliminary Investigation ◽  
Tensile Tests ◽  
Thermoplastic Composite ◽  
Ductile Deformation ◽  
Matrix Composites ◽  
Structure Property ◽  
Low Surface Energy ◽  
The Matrix

A preliminary investigation of interrelationships between tensile stress-strain characteristics and morphology evolution during deformation is conducted on a commercially available thermoplastic composite with a low-surface-energy nanofibrillating poly(tetrafluoroethylene) (PTFE) additive. In this class of composites, the deformation-associated nanofibrillation of the low-surface-energy additive has been hypothesized to provide an additional dissipation mechanism, thereby enhancing the ductility of the composite. This class of composites offers potential for automotive light weighting in exterior and interior body and fascia applications; it is therefore of interest to investigate processing-structure-property interrelationships in these materials. This study specifically probes the interrelationships between the plastic deformation within the matrix and the fibrillation of the low-surface-energy additive; tensile tests are carried out at two different temperatures which are chosen so as to facilitate and suppress plastic deformation within the matrix polymer. Based on these preliminary investigations, it is noted that PTFE fibrillation acts synergistically with the ductile deformation of the matrix resin resulting in higher strains to failure of the composite; the results also suggest that the mechanism of fibrillation-assisted enhancement of strains to failure may not operate in the absence of matrix plasticity.

scholarly journals Experimental Research on Bond Behaviour of Fabric Reinforced Cementitious Matrix Composites for Retrofitting Masonry Walls

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Fayu Wang ◽  
Nicholas Kyriakides ◽  
Christis Chrysostomou ◽  
Eleftherios Eleftheriou ◽  
Renos Votsis ◽  
...  
Keyword(s):  
Large Scale ◽  
Tensile Tests ◽  
Seismic Resistance ◽  
Matrix Composites ◽  
Bond Behaviour ◽  
Cementitious Matrix ◽  
The Matrix ◽  
Rc Frame Buildings ◽  
Direct Tensile ◽  
Fabric Reinforced Cementitious Matrix

AbstractFabric reinforced cementitious matrix (FRCM) composites, also known as textile reinforced mortars (TRM), an inorganic matrix constituting fibre fabrics and cement-based mortar, are becoming a widely used composite material in Europe for upgrading the seismic resistance of existing reinforced concrete (RC) frame buildings. One way of providing seismic resistance upgrading is through the application of the proposed FRCM system on existing masonry infill walls to increase their stiffness and integrity. To examine the effectiveness of this application, the bond characteristics achieved between (a) the matrix and the masonry substrate and (b) the fabric and the matrix need to be determined. A series of experiments including 23 material performance tests, 15 direct tensile tests of dry fabric and composites, and 30 shear bond tests between the matrix and brick masonry, were carried out to investigate the fabric-to-matrix and matrix-to-substrate bond behaviour. In addition, different arrangements of extruded polystyrene (XPS) plates were applied to the FRCM to test the shear bond capacity of this insulation system when used on a large-scale wall.

Effect of pouring temperature on A356-TiB2 MMCs cast in sand and permanent moulds by in-situ method

2016 ◽  
Vol 25 (5-6) ◽  
pp. 165-169
Author(s):  
C. Rajaravi ◽  
P.R. Lakshminarayanan
Keyword(s):  
Evaluation Studies ◽  
Physical And Mechanical Properties ◽  
Xrd Analysis ◽  
Matrix Composites ◽  
Structure Property ◽  
Pouring Temperature ◽  
Matrix Metal ◽  
Property Evaluation ◽  
The Matrix

AbstractThe paper describes a different condition of pouring temperature by sand and permanent mould to produce A356-6 wt% TiB2 metal matrix composites by in-situ method salt metal reaction route. The observation of SEM micrographs shows particle distribution of the TiB2 and it appears in hexagonal shape in Al matrix. The results of X-ray diffraction (XRD) analysis confirmed the formation of those TiB2 particulates and the results showed TiB2 particles are homogeneously dispersed throughout the matrix metal. Subsequent structure-property evaluation studies indicated sub-micron size reinforcement of in-situ formed TiB2 particles with improved physical and mechanical properties as compared to sand and permanent mould of Al-TiB2 composites. From, the permanent mould Al-TiB2 composite has an advantage of increase the properties over sand mould Al-TiB2 composite.

Mechanical Behavior of Microwave Processed Polymer Matrix Composites: the Effect Of The Temperature Increase Rate

1996 ◽  
Vol 430 ◽  
Author(s):  
M. Delmotte ◽  
J. Fitoussi ◽  
J. Toftegaard-Hansen ◽  
C. More ◽  
H. Jullien ◽  
...  
Keyword(s):  
Polymer Matrix Composites ◽  
Tensile Tests ◽  
Crosslinking Reaction ◽  
Matrix Composites ◽  
Mechanical Behaviors ◽  
Homogenous Distribution ◽  
Increase Rate ◽  
The Matrix ◽  
Matrix Flow ◽  
Experimental Pressure

AbstractMicrowave processed glass reinforced epoxies or glass reinforced polyesters exhibit mechanical behaviors different from conventionally cured materials, relatively to tensile tests. The faster increases of temperature due to microwaves cause a competition between the matrix flow and the crosslinking reaction which can be estimated by porosity variations. Higher mechanical moduih are also obtained, because of both an effect on chemical kinetics and a more homogenous distribution of temperature in materials. Nevertheless, to provide such specific mechanical behaviors in microwave processed composite materials, a best control of the experimental pressure parameters is requested.

Micromechanical theory and uniaxial tensile tests of fiber reinforced cement composites

1991 ◽  
Vol 6 (11) ◽  
pp. 2463-2473 ◽  
Author(s):  
C.C. Yang ◽  
T. Mura ◽  
S.P. Shah
Keyword(s):  
Volume Fraction ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Cement Composites ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Theoretical Predictions ◽  
The Matrix ◽  
Reinforced Cement ◽  
Fracture Arrest

The mechanism of fracture arrest in brittle-matrix composites with strong, long fibers is analyzed by using the inclusion method. The maximum stress contribution of the matrix in composites is discussed in this paper. A critical volume fraction of fibers fc is theoretically derived. If the volume fraction f is less than fc, then debonding between fibers and matrix occurs before the crack propagates through the whole section. If f is greater than fc, then no debonding occurs before the crack propagates through the whole section. The value of fc depends on the matrix and fiber properties and the bond character of the interface. To verify the analytical predictions, experiments on fiber reinforced cement composites subjected to uniaxial tension were conducted. The results of the theoretical predictions were also compared satisfactorily with other published experimental data.

scholarly journals Recycled Porcine Bone Powder as Filler in Thermoplastic Composite Materials Enriched with Chitosan for a Bone Scaffold Application

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2751
Author(s):  
Marco Valente ◽  
Jordi Puiggalí ◽  
Luis J. del Valle ◽  
Gioconda Titolo ◽  
Matteo Sambucci
Keyword(s):  
Composite Materials ◽  
Preliminary Investigation ◽  
Antibacterial Properties ◽  
Tensile Tests ◽  
Strength Properties ◽  
Thermoplastic Composite ◽  
Synthesis Process ◽  
Electrospinning Technique ◽  
Bone Powder ◽  
Biological Tests

This work aims to synthesize biocompatible composite materials loaded with recycled porcine bone powder (BP) to fabricate scaffolds for in-situ reconstruction of bone structures. Polylactic acid (PLA) and poly(ε-caprolactone) (PCL) were tested as matrices in percentages from 40 wt% to 80 wt%. Chitosan (CS) was selected for its antibacterial properties, in the amount from 5 wt% to 15 wt%, and BP from 20 wt% to 50 wt% as active filler to promote osseointegration. In this preliminary investigation, samples have been produced by solvent casting to introduce the highest possible percentage of fillers. PCL has been chosen as a matrix due to its greater ability to incorporate fillers, ensuring their adequate dispersion and lower working temperatures compared to PLA. Tensile tests demonstrated strength properties (6–10 MPa) suitable for hard tissue engineering applications. Based on the different findings (integration of PLA in the composite system, improvements in CS adhesion and mechanical properties), the authors supposed an optimization of the synthesis process, focused on the possible implementation of the electrospinning technique to develop PCL-BP composites reinforced with PLA-CS microfibers. Finally, biological tests were conducted to evaluate the antibacterial activity of CS, demonstrating the applicability of the materials for the biomedical field.

Production and characterization of Al 2024 matrix composites reinforced with β-Al3Mg2 complex metallic alloy particles

2013 ◽  
Vol 1517 ◽  
Author(s):  
Xiaorui Wang ◽  
Sergio Scudino ◽  
Jürgen Eckert
Keyword(s):  
Plastic Deformation ◽  
High Temperature Strength ◽  
Low Density ◽  
Matrix Composites ◽  
Specific Strength ◽  
Alloy Particles ◽  
The Matrix ◽  
Lightweight Composites ◽  
Al 2024

ABSTRACTIn this work, composites consisting of the Al 2024 matrix reinforced with β-Al3Mg2 particles have been produced by powder metallurgy with the aim of increasing the strength of the matrix and, at the same time, reducing the density of the material. The β-Al3Mg2 phase represents an ideal candidate as reinforcement in lightweight composites due to its low density and high-temperature strength. The β-Al3Mg2 reinforcement remarkably improves the mechanical properties of the 2024 matrix. In particular, the composite with 20 vol.% reinforcement display yield and compressive strengths exceeding that of the unreinforced matrix by about 120 and 180 MPa, while retaining appreciable plastic deformation of about 30 %. The strength of the material is further increased for the samples with 30 and 40 vol.% of β-Al3Mg2 phase, however, the composites show reduced plastic deformation of 11 and 4.5 %. Furthermore, the addition of the low-density β-Al3Mg2 particles decreases the density of the materials below that of the unreinforced 2024 matrix, considerably increasing the specific strength of the composites.

scholarly journals Characterization of Titanium Metal Matrix Composites (Ti-MMC) Made Using Different Manufacturing Routes

2021 ◽  
Author(s):  
Luigi Sanguigno ◽  
Marcello Antonio Lepore ◽  
Angelo Rosario Maligno
Keyword(s):  
Composite Laminates ◽  
Metal Matrix ◽  
Mechanical Performance ◽  
Tensile Tests ◽  
Morphological Properties ◽  
Elastic Behaviour ◽  
Matrix Composites ◽  
Micromechanical Modelling ◽  
The Matrix

The mechanical and morphological properties of the unidirectional metal matrix composite (MMC) in titanium alloy reinforced with continuous silicon carbide (SiC) fibres are investigated. The lay-up manufacturing process known as the Foil / Fibre (FF) lay-up was compared with the matrix-coated-fibre (CF) method which promises a better final shape of the reinforcing fibre net. Tensile tests were performed to measure mechanical performance of the manufactured MMCs both longitudinally and transversely respect to the direction of SiC fibres. Elastic behaviour of the investigated MMCs was assumed orthotropic and related to mechanical properties and spatial distribution of the MMC constituents: SiC fibres and Titanium (Ti) matrix. This was achieved using micromechanical modelling based on Finite Element (FE) calculations. FE micromechanical modelling was carried out on the Representative Elementary Volume (REV) of the MMC microstructure resolved by non-destructive analysis such as X-Ray tomography. The analysis carried out highlighted and justified mechanical performance difference between composite laminates containing the same amount of SiC reinforcement fibres for unit of volume but made following different manufacturing routes. To compute overall orthotropic behaviour of the MMC laminate, each constituent was assumed as an elastic isotropic heterogeneity during the averaging. This simplify assumption was validated by comparison with experimental data during the mechanical characterization of the investigated MMC composites.

scholarly journals Influence of PVAc/PVA Hydrolysis on Additive Surface Activity

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 205 ◽  
Author(s):  
Ophélie Squillace ◽  
Rebecca Fong ◽  
Oliver Shepherd ◽  
Jasmine Hind ◽  
James Tellam ◽  
...  
Keyword(s):  
Surface Energy ◽  
Surface Activity ◽  
Polymer Matrix ◽  
Surface Segregation ◽  
High Surface ◽  
Sodium Dodecyl ◽  
Degree Of Hydrolysis ◽  
Low Surface Energy ◽  
Wide Range ◽  
The Matrix

This aims to establish design rules for the influence of complex polymer matrices on the surface properties of small molecules. Here, we consider the dependence of the surface behaviour of some model additives on polymer matrix hydrophobicity. With stoichiometric control over hydrolysis, we generate systematic changes in matrix chemistry from non-polar, hydrophobic PVAc to its hydrolysed and hydrophilic analogue, PVA. With the changing degree of hydrolysis (DH), the behaviour of additives can be switched in terms of compatibility and surface activity. Sorbitol, a polar sugar-alcohol of inherently high surface energy, blooms to the surface of PVAc, forming patchy domains on surfaces. With the increasing DH of the polymer matrix, its surface segregation decreases to the point where sorbitol acts as a homogeneously distributed plasticiser in PVA. Conversely, and despite its low surface energy, octanoic acid (OA) surprisingly causes the increased wettability of PVAc. We attribute these observations to the high compatibility of OA with PVAc and its ability to reorient upon exposure to water, presenting a hydrophilic COOH-rich surface. The surfactant sodium dodecyl sulfate (SDS) does not show such a clear dependence on the matrix and formed wetting layers over a wide range of DH. Interestingly, SDS appears to be most compatible with PVAc at intermediate DH, which is consistent with the amphiphilic nature of both species under these conditions. Thus, we show that the prediction of the segregation is not simple and depends on multiple factors including hydrophobicity, compatibility, blockiness, surface energy, and the mobility of the components.

Effect of Y2O3 Coating on the Interface and Mechanical Properties of SiC Fiber Reinforced GH4738 Composites

2017 ◽  
Vol 898 ◽  
pp. 604-608 ◽  
Author(s):  
Pei Huan Li ◽  
Yong Zhang ◽  
Xuan Hui Qu
Keyword(s):  
Mechanical Properties ◽  
Hot Isostatic Pressing ◽  
Tensile Tests ◽  
Interfacial Reactions ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Sic Fiber ◽  
Elevated Temperature Tensile ◽  
Barrier Coating ◽  
The Matrix

To prevent the strong interfacial reactions in SiC fiber reinforced nickel-based superalloys matrix composites, yttrium oxide (Y2O3) was used as the barrier coating by reaction magnetron sputtering method. Compared with the composites without coating, after the high temperature hot isostatic pressing (HIP), Y2O3 coating effectively protected the SiC fibers from the interfacial reactions, and no element diffusion can be observed between the fibers and the matrix. The elevated temperature tensile tests were performed on both SiC/GH4738 and SiC/Y2O3/GH4738 composite. The results indicated that the strength of the composites with Y2O3 coating can increase about 35% in comparison with the composites without coating.

scholarly journals MWCNT-Reinforced AA7075 Composites: Effect of Reinforcement Percentage on Mechanical Properties

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 969
Author(s):  
Iria Feijoo ◽  
Gloria Pena ◽  
Marta Cabeza ◽  
M. Julia Cristóbal ◽  
Pilar Rey
Keyword(s):  
Multiwall Carbon Nanotubes ◽  
Tensile Tests ◽  
High Energy ◽  
Milling Process ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Strip Shape ◽  
The Matrix ◽  
Micro Deformation ◽  
Scherrer Formula

Metal–matrix composites (MMC) of aluminium alloy 7075 (AA7075) containing 1 wt.% and 0.5 wt.% multiwall carbon nanotubes (MWCNTs) were developed by powder metallurgy, using a high energy ball milling (HEBM) process for dispersion of the MWCNTs. The powder of the AA7075-MWCNT obtained was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The microstructural changes produced during the milling process, such as the modification of the crystallite size, as well as the micro-deformation of the matrix crystal lattice, were determined using the Scherrer formula. After consolidation into a strip shape using the hot powder extrusion (HPE) process at 500 °C, no porosity was detected and a fine homogeneous dispersion of the reinforcement into the matrix was obtained. After performing a 0.2 HV test and tensile tests in the extruded profiles of both composites, a better combination of properties was found in samples of AA7075-0.5 wt.% MWCNT, with the increase in measured ductility being especially remarkable.

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