Friction and Wearing Behaviour of Sintered Composites Made from Copper Mixed with Carbon Fibers

2015 ◽  
Vol 660 ◽  
pp. 81-85 ◽  
Author(s):  
Radu Caliman
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Composite Materials ◽  
Friction Coefficient ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Coefficient Of Thermal Expansion ◽  
Density Ratio ◽  
Point Of View ◽  
Short Carbon

This paper presents a study regarding friction and wear comportment of sintered composite materials obtained by mixture of copper with short carbon fibers. Sintered composites are gaining importance because the reinforcement serves to reduce the coefficient of thermal expansion and increase the strength and modulus. In case of composites form by carbon fiber and copper, the thermal conductivity can also be enhanced. The combination of low thermal expansion and high thermal conductivity makes them very attractive for electronic packaging. Besides good thermal properties, their low density makes them particularly desirable for aerospace electronics and orbiting space structures. Compared to the metal itself, a carbon fiber-copper composite is characterized by a higher strength-to-density ratio, a higher modulus-to-density ratio, better fatigue resistance, better high-temperature mechanical properties and better wear resistance. Varying the percentage of short carbon fibers from 7,8% to 2,4%, and the percentage of copper from 92,2% to 97,6%, five dissimilar composite materials have been made and tested from the wear point of view. Friction tests are carried out, at room temperature, in dry conditions, on a pin-on-disc machine. The friction coefficient was measured using abrasive discs made from steel 4340 having the average hardness of 40 HRC, and sliding velocity of 0,6 m/sec. The primary goal of this study work it was to distinguish a mixture of materials with enhanced friction and wearing behaviour. The load applied on the specimen during the tests, is playing a very important role regarding friction coefficient and also the wearing speed.

scholarly journals A method of manufactoring pipes from polymer composite materials for aircraft structures

2020 ◽  
Vol 26 (5) ◽  
pp. 228-27
Author(s):  
S.O. Odaisky ◽  
◽  
O.M. Potapov ◽  
S.V. Fedorenko ◽  
A.P. Shchudro ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Polymer Composite ◽  
Modulus Of Elasticity ◽  
Coefficient Of Thermal Expansion ◽  
Longitudinal Direction ◽  
Polymer Composite Materials ◽  
Thermophysical Characteristics ◽  
Reinforcement Scheme

The frame power structures are widely applied when designing aircraft, in which composite rod elements are used to reduce the mass and size characteristics. To solve the problem of manufacturing rod elements from polymer composite materials, we developed a technology for the manufacture of carbon fiber pipes using an existing machine for winding carbon fiber, which provides the necessary strength and rigidity mainly in the longitudinal direction.When calculating the rod elements, all the loads that will affect the structure as well as the coefficient of thermal expansion should be taken into account. To achieve the required physical, mechanical, and thermophysical characteristics, the optimal scheme of reinforcement is the scheme with a quasi-longitudinal direction of the fibers. We developed the method of manufacturing based on the technology allowing us to obtain a reinforcement scheme with fiber orientation in the quasi-longitudinal direction with a reinforcement angle of about 1° by a combined method of layer-by-layer winding of carbon fiber. As a result of technological testing, we obtained samples of carbon fiber rod elements, which were used to confirm the calculated characteristics. To confirm the physico-mechanical and thermophysical characteristics, we determined the assessment of limit of strength and modulus of elasticity in bending, the limit of strength and modulus of elasticity in torsion, the limit of strength and modulus of elasticity in compression, and the coefficient of thermal expansion. The obtained characteristics of the dependences of the elasticity modulus of the pipe prototype material at the fibers’ orientation angle correlate with theoretical calculations. The presented method has the patent UA 128613 U.

Structural and Thermal Properties of Hot Pressed Cu/C Matrix Composites Materials Used for the Thermal Management of High Power Electronic Devices

2007 ◽  
Vol 534-536 ◽  
pp. 1505-1508 ◽  
Author(s):  
Pierre Marie Geffroy ◽  
Jean François Silvain
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Carbon Fibers ◽  
Volume Fraction ◽  
Coefficient Of Thermal Expansion ◽  
Copper Matrix ◽  
Matrix Composites ◽  
Porosity Level ◽  
Materials Used ◽  
Short Carbon

In order to obtain materials for electronic applications that exhibit both excellent thermal conductivity and low coefficient of thermal expansion (CTE), copper matrix composites have been reinforced by short high modulus graphite fibers. The lack of fiber/matrix interaction prevents any degradation of the carbon reinforcement during the elaboration steps and the normal use of these materials. Elaboration conditions, such as mixing conditions of the short carbon fibers and the copper powder, dimension and shape of the two powders, and finally densification atmosphere, temperature, pressure and time, have been optimized. Main parameters involved in the thermal properties of the Cu/C composite materials have been analyzed and adjusted. CTE is mainly related with the carbon volume fraction; CTE ranging from 9 to 13 10-6/°C can be reproductively obtained with carbon volume fraction ranging from 50% to 20%. Thermal conductivity properties are more complex and are linked mainly with 1) the porosity level inside the material, and 2) the orientation, properties and volume fraction of the carbon fibers. For short carbon fibers, in plane thermal conductivity ranging from 200 to 550 W/mK have been reproductively measured associated with thermal conductivity through-thickness ranging from 150 to 300 W/mK.

The Influence of Sliding Velocity on the Wear Intensity in Case of Polymeric Composite Materials Reinforced with Short Carbon Fibers

2014 ◽  
Vol 1036 ◽  
pp. 9-12
Author(s):  
Radu Caliman
Keyword(s):  
Composite Materials ◽  
Friction Coefficient ◽  
Carbon Fibers ◽  
High Resistance ◽  
Research Work ◽  
Polymeric Composite ◽  
Tantalum Carbide ◽  
Sliding Velocity ◽  
Polymeric Composite Materials ◽  
Short Carbon

This paper presents a study of the tribological properties of polymeric composite materials reinforced with short carbon fibers. Reinforces carbon fibers materials are more effective if refer to specific properties per unit volume compared to conventional isotropic materials. Potential benefits of carbon fibers composite materials are: high resistance to breakage and high value ratios strength/density; resistance to high temperatures; low density and high resistance to wear; low or high friction coefficient. The composites are complex and versatile materials; their versatility it is given by the multitude of choice variety of the constituent materials that can be combined to obtain the desired properties of otherwise unobtainable from conventional materials. The composite materials used in this research work are obtained combining epoxy with short carbon fibers with titanium carbide and tantalum carbide in order to investigate the variation of the friction coefficient for three different sliding velocities. Varying the percent of epoxy from 29,35% to 43,92% and the percent of short carbon fibers from 35,43% to 53,70%, nine different composite materials are obtained and tested. Friction tests are carried out, at room temperature, in dry conditions, on a pin-on-disc machine. The friction coefficient was measured maintaining constant the pressing force (8 daN) and sliding time (120 sec), and varying the sliding velocity to 8, 14 and 23 m/sec. The main objective of this research work it was to identify a composite material with higher friction coefficient.

Processing and Thermal Properties of Cu-AlN Composites

2010 ◽  
Vol 65 ◽  
pp. 100-105 ◽  
Author(s):  
Marcin Chmielewski ◽  
Katarzyna Pietrzak ◽  
Dariusz Kaliński ◽  
Agata Strojny
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Composite Materials ◽  
Coefficient Of Thermal Expansion ◽  
Processing Parameters ◽  
Process Conditions ◽  
Pressing Method ◽  
Materials Used ◽  
Effective Transfer

Heat transfer by conduction is involved in the use of heat sinks dissipitating heat from electronic devices. Effective transfer of heat requires using materials of high thermal conductivity. In addition, it requires appropriate values of thermal expansion, matched to the semiconductor materials, high purity of materials used and good contact between bonded elements across which heat transfer occurs. The conventional materials are not able to fulfil still raising and complex requirements. The solutions of this problem could be using the composites materials, where the combinations of different properties is possible to use. This study presents the technological tests and the analysis of correlation between processing parameters and the properties of copperaluminium nitride composites. Composite materials were obtained by mixing in planetary ball mill and then densified using the sintering under pressure or hot pressing method. The microstructure of obtained composite materials using optical microscopy and scanning electron microscopy were analyzed. Coefficient of thermal expansion (CTE) and thermal conductivity (TC) were investigated depending on the process conditions.

scholarly journals Absorption and Strength Properties of Short Carbon Fiber Reinforced Mortar Composite

Buildings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 300
Author(s):  
Md. Safiuddin ◽  
George Abdel-Sayed ◽  
Nataliya Hearn
Keyword(s):  
Tensile Strength ◽  
Carbon Fiber ◽  
Water Absorption ◽  
Carbon Fibers ◽  
Strength Properties ◽  
Fiber Content ◽  
Test Results ◽  
Air Content ◽  
Entrapped Air ◽  
Short Carbon

This paper presents the water absorption and strength properties of short carbon fiber reinforced mortar (CFRM) composite. Four CFRM composites with 1%, 2%, 3%, and 4% short pitch-based carbon fibers were produced in this study. Normal Portland cement mortar (NCPM) was also prepared for use as the control mortar. The freshly mixed mortar composites were tested for workability, wet density, and entrapped air content. In addition, the hardened mortar composites were examined for compressive strength, splitting tensile strength, flexural strength, and water absorption at the ages of 7 and 28 days. The effects of different carbon fiber contents on the tested properties were observed. Test results showed that the incorporation of carbon fibers decreased the workability and wet density, but increased the entrapped air content in mortar composite. Most interestingly, the compressive strength of CFRM composite increased up to 3% carbon fiber content and then it declined significantly for 4% fiber content, depending on the workability and compaction of the mortar. In contrast, the splitting tensile strength and flexural strength of the CFRM composite increased for all fiber contents due to the greater cracking resistance and improved bond strength of the carbon fibers in the mortar. The presence of short pitch-based carbon fibers significantly strengthened the mortar by bridging the microcracks, resisting the propagation of these minute cracks, and impeding the growth of macrocracks. Furthermore, the water absorption of CFRM composite decreased up to 3% carbon fiber content and then it increased substantially for 4% fiber content, depending on the entrapped air content of the mortar. The overall test results suggest that the mortar with 3% carbon fibers is the optimum CFRM composite based on the tested properties.

Thermal Property Evaluation of Chilled Aluminum-Alumina MMC

2015 ◽  
Vol 1101 ◽  
pp. 79-82
Author(s):  
B.C. Suresh ◽  
S.B. Arun
Keyword(s):  
Thermal Expansion ◽  
Composite Materials ◽  
Thermal Property ◽  
Coefficient Of Thermal Expansion ◽  
Matrix Material ◽  
High Strength ◽  
Stir Casting ◽  
Al Alloy ◽  
Industrial Growth ◽  
Property Evaluation

Now a day’s composite materials are taking very important role in industrial growth. Composite materials are widely used in Automobiles, aerospace, submarine and also in other major fields, due to their special characteristics like light weight, high strength, stiffness, corrosion resistance. The determination of Coefficient of Thermal Expansion (CTE) of MMCs is important to aid its usage in high temperature environment as in the case of automobile combustion chamber. In these applications the stability of the composites over a long period of operation is a critical design considerationPresent work deals with the thermal property evaluation of the Al alloy / alumina metal matrix composite developed using the Stir Casting with chilling route technique. LM 26 Al alloy is being selected as the matrix material as it is a potential alloy for automotive piston applications. Al alloy / alumina MMCs was cast under end chilling technique by dispersing the reinforcement from 6 to 12 wt% the steps of 3% to study the variation in its thermal properties. At the same time chill material is also changed (Copper and MS) for different composition of MMCs cast to study the thermal behavior variations. After casting the required MMC, test specimens were prepared as per the standards to conduct thermal conductivity (K) tests and coefficient of thermal expansion (CTE) tests. Above tests were repeated for different composites containing different weight % of dispersed cast using different chills.

Evaluation of CeSZ Thermal Barrier Coatings for Diesels

2000 ◽  
Author(s):  
P.J. Huang ◽  
J.J. Swab ◽  
P.J. Patel ◽  
W.S. Chu
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Barrier Coatings ◽  
Coefficient Of Thermal Expansion ◽  
Fuel Efficiency ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Mechanical And Thermal Properties ◽  
Barrier Coatings ◽  
Spray Process

Abstract The development of thermal barrier coatings (TBCs) for diesel engines has been driven by the potential improvements in engine power and fuel efficiency that TBCs represent. TBCs have been employed for many years to reduce corrosion of valves and pistons because of their high temperature durability and thermal insulative properties. There are research programs to improve TBCs wear resistance to allow for its use in tribologically intensive areas of the engine. This paper will present results from tribological tests of ceria stabilized zirconia (CeSZ). The CeSZ was applied by atmospheric plasma spray process. Various mechanical and thermal properties were measured including wear, coefficient of thermal expansion, thermal conductivity, and microhardness. The results show the potential use of CeSZ in wear sensitive applications in diesel applications. Keywords: Thermal Barrier Coating, Diesel Engine, Wear, Thermal Conductivity, and Thermal Expansion

A Study on Thermal and Electrical Conductivities of Ethylene-Butene Copolymer Composites with Carbon Fibers

2021 ◽  
Vol 36 (4) ◽  
pp. 417-422
Author(s):  
Y. Hamid ◽  
P. Svoboda
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Carbon Fiber ◽  
Electric Conductivity ◽  
Carbon Fibers ◽  
Mechanical Strain ◽  
Electric Resistance ◽  
Resistance Change ◽  
Electrical Conductivities ◽  
Fiber Sample

Abstract Ethylene-butene copolymer (EBC)/carbon-fiber (CF) composites can be utilized as an electromechanical material due to their ability to change electric resistance with mechanical strain. The electro-mechanical properties and thermal conductivity of ethylene butene copolymer (EBC) composites with carbon fibers were studied. Carbon fibers were introduced to EBC with various concentrations (5 to 25 wt%). The results showed that carbon fibers’ addition to EBC improves the electric conductivity up to 10 times. Increasing the load up to 2.9 MPa will raise the electric resistance change by 4 500% for a 25% fiber sample. It is also noted that the EBC/CF composites’ electric resistance underwent a dramatic increase in raising the strain. For example, the resistance change was around 13 times higher at 15% strain compared to 5% strain. The thermal conductivity tests showed that the addition of carbon fibers increases the thermal conductivity by 40%, from 0.19 to 0.27 Wm–1K–1.

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