scholarly journals Mechanical behaviour of Composites based on Diss and Aflfa fibres in different matrices

2020 ◽  
Vol 330 ◽  
pp. 01051
Author(s):  
Zohra Belkhir ◽  
Mouloud Merzoud ◽  
Amar Benazzouk
Keyword(s):  
Natural Fibers ◽  
Water Soluble ◽  
Experimental Program ◽  
Matrix Composites ◽  
Good Adhesion ◽  
Brittle Behavior ◽  
The Matrix ◽  
Clay Matrix ◽  
Ductile Behavior ◽  
Soluble Components

The use of natural fibers in cementitious matrices has an incompatibility, which results considerable retardation of setting and very low resistances during the composite tests with natural crushed Diss, despite the fact that the fibers have considerable tensile strengths, because of the sugars and water- soluble components contained in natural plants. To improve the fibers contribution in cementitious composites, we have carried out a treatment by boiling the natural fibers to extract the substances responsible for the bad connection between fibers and the cement paste. This phenomenon of incompatibility disappears with the use of clay matrix or lime, which allows using the fibers without any treatment. We were able to determine the mechanical behavior of composites in flexion and compression by measuring stresses and deformations. Through our vast experimental program on the composites of natural fibers of Alfa and Diss in different matrices (cement and clay) and different sizes ranging from 2 to 8 cm, we have found: 1) The best resistance in bending and compression are generally reached for the composites with fibers having the dimensions between 4 and 6 cm. 2) The best bending strengths are achieved for composites with cementitious matrices, because of the good adhesion of the fibers to the matrix. 3) The best compressive strengths are achieved for clay matrix composites, which are due to the good compressibility of the clay. 4) The composites of Alfa and Diss fibers presented a very ductile behavior as well in flexion as in compression, contrary to the pure binder paste which has a brittle behavior. 5) The composites obtained have a very low density, which makes it possible to classify them as lightweight materials and have a very ductile behavior, which suggests using these materials as filling in the seismic zones.

scholarly journals Interfacial Aspects of Metal Matrix Composites Prepared from Liquid Metals and Aqueous Solutions: A Review

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1400
Author(s):  
Peter Baumli
Keyword(s):  
Aqueous Solutions ◽  
Physical Properties ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Liquid Metals ◽  
Interfacial Phenomena ◽  
Matrix Composites ◽  
Good Adhesion ◽  
Mechanical And Physical Properties ◽  
The Matrix

The paper reviews the preparation of the different metallic nanocomposites. In the preparation of composites, especially in the case of nanocomposites, interfacial phenomena play an important role. This review summarizes the literature on various interfacial phenomena, such as wettability and reactivity in the case of casting techniques and colloidal behavior in the case of electrochemical and electroless methods. The main contribution of this work lies in the evaluation of collected interfacial phenomena and difficulties in the production of metal matrix composites, for both nano-sized and micro-sized reinforcements. This study can guide the composite maker in choosing the best criteria for producing metal matrix composites, which means a real interface with good adhesion between the matrix and the reinforcement. This criterion results in desirable mechanical and physical properties and homogenous dispersion of the reinforcement in the matrix.

Polymer-Modified Calcium-Aluminate Macro Defect Free (MDF) Cements

2019 ◽  
Vol 957 ◽  
pp. 311-318 ◽  
Author(s):  
Raffaella Dell’Aversano
Keyword(s):  
High Performance ◽  
Standard Form ◽  
Ceramic Materials ◽  
Water Soluble ◽  
Water Soluble Polymers ◽  
Soluble Polymers ◽  
Brittle Behavior ◽  
Complex Forms ◽  
Ductile Behavior ◽  
Cement Strength

Cementitious Macro Defect Free (MDF) materials can be obtained in complex forms with high performance making these materials suitable for applications in many sectors. The low water to cement ratio, w/c, and the saturation of voids by means of water soluble polymers allows increasing the cement strength. However, in their standard form these materials show both the sensitivity typical of water-soluble polymers, presenting a low glass transition temperature (Tg), and the brittle behavior typical of ceramic materials and therefore low toughness. The aim of this work is to modify with various techniques the standard formulation of MDF materials by modulating toughness from a brittle to a ductile behavior. In addition, the effect of the recipes modifications will be analyzed by comparing the rheological characteristics along the processing stages.

Sol-gel Elaboration of Porous Oxide Coatings as Interphase in SiC/SiC Ceramic Matrix Composites

2003 ◽  
Vol 775 ◽  
Author(s):  
M. Verdenelli ◽  
S. Parola ◽  
F. Chassagneux ◽  
S. Jacques ◽  
H. Vincent ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Ceramic Matrix Composites ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Brittle Behavior ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
The Matrix ◽  
Mesoporous Oxide

AbstractCombinations of meso-, macro- and microporous coatings with a chemical composition of 90%Al2O3-10%SiO2 were elaborated on SiC Hi-Nicalon fibers using the sol-gel process. They were evaluated as porous interphase for the reinforcement of CMC. The mesoporous oxide, in contact with the fiber, allows cracks deviation whereas the macroporous one, in contact with the matrix, avoids the gaseous infiltration of the mesopores during the SiC CVD matrix process. It also prevents from oxygen diffusion during high temperature under air. The characterization of the composites was performed by SEM (scanning electron microscopy), TEM (transmission electron microscopy), X-ray diffraction, and EDS (energy dispersive spectrometry). TEM evidenced the porosity gradient as expected. A tensile test on the composites revealed brittle behavior (fracture) and no fiber debonding was observed.

scholarly journals Manufacture of student chair in composite material reinforced with fique fiber

2021 ◽  
Vol 26 (1) ◽  
pp. 6-13
Author(s):  
Sergio Andrés Gómez ◽  
Edwin Cordoba ◽  
Christian Vega Mesa ◽  
Sergio Gómez Becerra
Keyword(s):  
Composite Material ◽  
Polyester Resin ◽  
Natural Fibers ◽  
Environmental Damage ◽  
Good Adhesion ◽  
Sustainable Products ◽  
Reinforced Composite ◽  
The Matrix ◽  
Reinforced Composite Material

The use of natural fibers as reinforcement for composite materials is on the rise due to the need to reduce environmental damage and manufacture sustainable products. One of the fibers used for this purpose is fique fiber. This article describes the manufacture of a student chair with fique fiber-reinforced composite material. To choose the amount of reinforcement to be used in the elaboration of the chair, the mechanical characterization of several composites with different percentages of the fiber was carried out, where it was found that both the flexural and tensile properties increased with a higher insertion of fique. The selected material was analyzed morphologically with optical microscopy, finding that there was good adhesion between the fiber and the matrix. A simulation with finite elements showed that the chair would resist a load of 100 kg. The student chair was manufactured using the Hand Lay Up technique with material composed of fique fiber and polyester resin.

Composite Materials Types and Applications

2018 ◽  
pp. 1-29
Keyword(s):  
Natural Fiber ◽  
Natural Fibers ◽  
Ceramic Matrix Composites ◽  
Polymeric Composites ◽  
World Market ◽  
Matrix Composites ◽  
Research Fields ◽  
Textile Fabrics ◽  
Unique Material ◽  
The Matrix

A composite is composed from two or more different materials that are combined together to create a superior and unique material. Composites are divided into three main categories according to the matrix type; Metal Matrix Composites, Ceramic Matrix Composites and Fiber Reinforced Polymeric Composites. In this chapter, a general overview of these categories will be done. More emphasis is on polymeric composites reinforced by textile fabrics. A brief introduction of synthetic and natural fibers is presented. Also, a general investigation on the world market of natural fiber concerning the production, development, research fields and main applications will be provided.

scholarly journals Experimental characterization of tensile properties of epoxy resin by using micro-fiber specimens

2016 ◽  
Vol 35 (24) ◽  
pp. 1792-1801 ◽  
Author(s):  
Jun Misumi ◽  
Raja Ganesh ◽  
Subramani Sockalingam ◽  
John W Gillespie
Keyword(s):  
Epoxy Resin ◽  
Surface Defects ◽  
Failure Strain ◽  
Fiber Volume ◽  
Length Scales ◽  
Brittle Behavior ◽  
Reinforced Plastic ◽  
Bulk Film ◽  
The Matrix ◽  
Ductile Behavior

In unidirectional carbon fiber-reinforced plastic laminates, the distance between fibers can varies from submicron to micron length scales. The mechanical properties of the matrix at this length scale are not well understood. In this study, processing methods have been developed to produce high quality epoxy micro-fibers with diameters ranging from 100 to 150 µm that are used for tensile testing. Five types of epoxy resin systems ranging from standard DGEBA to high-crosslink TGDDM and TGMAP epoxy systems have been characterized. Epoxy macroscopic specimens with film thickness of 3300 µm exhibited brittle behavior (1.7 to 4.9% average failure strain) with DGEBA resin having the highest failure strain level. The epoxy micro-fiber specimens exhibited significant ductile behavior (20 to 42% average failure strain) with a distinct yield point being observed in all five resin systems. In addition, the ultimate stress of the highly cross-linked TGDDM epoxy fiber exceeded the bulk film properties by a factor of two and the energy absorption was over 50 times greater on average. The mechanism explaining the dramatic difference in properties is discussed and is based on size effects (the film volume is about 2000 times greater than the fiber volume within the gage sections) and surface defects. Based on the findings presented in this paper, the microscale fiber test specimens are recommended and provide more realistic stress–strain response for describing the role of the matrix in composites at smaller length scales.

Preparation of Electron Transparent Metal-Matrix Composites

1968 ◽  
Vol 26 ◽  
pp. 334-335 ◽  
Author(s):  
M. R. Pinnel ◽  
A. Lawley
Keyword(s):  
Stainless Steel ◽  
Load Transfer ◽  
Volume Fraction ◽  
Steel Wire ◽  
Initial Step ◽  
Interfacial Region ◽  
Matrix Composites ◽  
Specific Test ◽  
The Matrix ◽  
The One

Numerous phenomenological descriptions of the mechanical behavior of composite materials have been developed. There is now an urgent need to study and interpret deformation behavior, load transfer, and strain distribution, in terms of micromechanisms at the atomic level. One approach is to characterize dislocation substructure resulting from specific test conditions by the various techniques of transmission electron microscopy. The present paper describes a technique for the preparation of electron transparent composites of aluminum-stainless steel, such that examination of the matrix-fiber (wire), or interfacial region is possible. Dislocation substructures are currently under examination following tensile, compressive, and creep loading. The technique complements and extends the one other study in this area by Hancock.The composite examined was hot-pressed (argon atmosphere) 99.99% aluminum reinforced with 15% volume fraction stainless steel wire (0.006″ dia.).Foils were prepared so that the stainless steel wires run longitudinally in the plane of the specimen i.e. the electron beam is perpendicular to the axes of the wires. The initial step involves cutting slices ∼0.040″ in thickness on a diamond slitting wheel.

Deformation at interfaces of Ti-6Al-4V/SiC fiber composites

1992 ◽  
Vol 50 (1) ◽  
pp. 158-159
Author(s):  
Warren J. Moberly ◽  
Daniel B. Miracle ◽  
S. Krishnamurthy
Keyword(s):  
Thermal Stresses ◽  
Load Transfer ◽  
Coefficient Of Thermal Expansion ◽  
Hot Isostatic Pressing ◽  
Matrix Composites ◽  
Ongoing Research ◽  
Aerospace Applications ◽  
Sic Fiber ◽  
The Matrix ◽  
Intermetallic Matrix Composites

Titanium-aluminum alloy metal matrix composites (MMC) and Ti-Al intermetallic matrix composites (IMC), reinforced with continuous SCS6 SiC fibers are leading candidates for high temperature aerospace applications such as the National Aerospace Plane (NASP). The nature of deformation at fiber / matrix interfaces is characterized in this ongoing research. One major concern is the mismatch in coefficient of thermal expansion (CTE) between the Ti-based matrix and the SiC fiber. This can lead to thermal stresses upon cooling down from the temperature incurred during hot isostatic pressing (HIP), which are sufficient to cause yielding in the matrix, and/or lead to fatigue from the thermal cycling that will be incurred during application, A second concern is the load transfer, from fiber to matrix, that is required if/when fiber fracture occurs. In both cases the stresses in the matrix are most severe at the interlace.

An SEM study of raphide crystal initials in the leaves of vitis (grape)

1995 ◽  
Vol 53 ◽  
pp. 984-985
Author(s):  
H. J. Arnott ◽  
M. A. Webb ◽  
L. E. Lopez
Keyword(s):  
Calcium Oxalate ◽  
Water Soluble ◽  
Calcium Oxalate Crystals ◽  
Calcium Oxalate Crystal ◽  
Oxalate Crystals ◽  
Large Numbers ◽  
Sem Study ◽  
The Matrix ◽  
Crystal Cells ◽  
Crystal Idioblast

Many papers have been published on the structure of calcium oxalate crystals in plants, however, few deal with the early development of crystals. Large numbers of idioblastic calcium oxalate crystal cells are found in the leaves of Vitis mustangensis, V. labrusca and V. vulpina. A crystal idioblast, or raphide cell, will produce 150-300 needle-like calcium oxalate crystals within a central vacuole. Each raphide crystal is autonomous, having been produced in a separate membrane-defined crystal chamber; the idioblast''s crystal complement is collectively embedded in a water soluble glycoprotein matrix which fills the vacuole. The crystals are twins, each having a pointed and a bidentate end (Fig 1); when mature they are about 0.5-1.2 μn in diameter and 30-70 μm in length. Crystal bundles, i.e., crystals and their matrix, can be isolated from leaves using 100% ETOH. If the bundles are treated with H2O the matrix surrounding the crystals rapidly disperses.

The Potential Migrated Mechanism of Water-Soluble Components in Pellets Prepared by Wet Extrusion/Spheronization: Effect of Drying Rate

2020 ◽  
Vol 17 ◽  
Author(s):  
Bingwei Wang ◽  
Jianping Liu ◽  
Zhenghua Li ◽  
Yulong Xia ◽  
Shuangshuang Zhang ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Water Soluble ◽  
In Vitro Dissolution ◽  
Drying Rate ◽  
Scanning Calorimetry ◽  
Drying Temperature ◽  
Wet Extrusion ◽  
Extrusion Spheronization ◽  
Soluble Components

Background: At present, there were numerous researches on the migration of components in tablets and granules, the investigation in the pharmaceutical literatrue concerning the effect of drying rate on the migration of water-soluble components of pellets was limited. Temperature and relative humidity (RH) were crucial parameters during the drying process which was an essential step in the preparation of pellets via wet extrusion/spheronization. To quantify these variables, the water loss percentage of pellets per minute was defined as drying rate. Objective: The study aimed to investigate the influence of drying rate on the migration of water-soluble components in wet pellets and the potential migrated mechanism. Methods: The pellets containing tartrazine as a water-soluble model drug and microcrystalline cellulose as a matrix former were prepared by extrusion/spheronization and dried at four different drying temperature and relative humidity. Afterward, the extent of migrated tartrazine was assessed regarding appearance, in-vitro dissolution test, Differential Scanning Calorimetry, X-Ray Powder Diffraction, Attenuated total reflectance Fourier transform infrared spectroscopy and Confocal Raman Mapping. Results: Results demonstrated that red spots of tartrazine appeared on the surface of pellets and more than 40% tartrazine were burst released within 5 minutes when pellets dried at 60℃/RH 10%. While pellets dried at 40℃/RH 80%, none of these aforementioned phenomena was observed. Conclusion: In conclusion, the faster drying rate was, the more tartrazine migrated to the exterior of pellets. Adjusting drying temperature and relative humidity appropriately could inhibit the migration of water-soluble components within wet extrusion/spheronization pellets.

Sign in / Sign up

Export Citation Format

Share Document