Influence of Coating Layer to Reduce Thermal Stresses in Cylindrically Formed Metal Matrix Composites

2000 â—½  
Author(s):  
Fuat Okumus â—½  
Aydin Turgut â—½  
Erol Sancaktar
Keyword(s):  
Thermal Expansion â—½  
Metal Matrix Composites â—½  
Metal Matrix â—½  
Thermal Stresses â—½  
Coating Layer â—½  
Coefficient Of Thermal Expansion â—½  
Aluminum Matrix â—½  
Matrix Composites â—½  
Cylinder Model â—½  
Matrix Layer

Abstract In this study, the use of coating layers is investigated to reduce thermal stresses in the metal matrix composites which have a mismatch in coefficients of thermal expansions in fiber and matrix components. The thermoelastic solutions are obtained based on a three-cylinder model. It is shown that the effectiveness of the layer can be defined by the product of its coefficient of thermal expansion and thickness. Consequently, a compensating layer with a sufficiently high coefficient of thermal expansion can reduce the thermal stresses in the metal matrix. The study is based on a concentric three cylinder model isolating individual steel fibers surrounded with a coating layer and an aluminum matrix layer. Only monotonic cooling is studied.

Diamond/Al metal matrix composites formed by the pressureless metal infiltration process

1993 â—½  
Vol 8 (5) â—½  
pp. 1169-1173 â—½  
Author(s):  
William B. Johnson â—½  
B. Sonuparlak
Keyword(s):  
Thermal Conductivity â—½  
Thermal Expansion â—½  
Metal Matrix Composites â—½  
Metal Matrix â—½  
Coefficient Of Thermal Expansion â—½  
Matrix Composites â—½  
Infiltration Process â—½  
Point Bend â—½  
Aluminum Metal Matrix Composites â—½  
Metal Infiltration

Diamond particles are unique fillers for metal matrix composites because of their extremely high modulus, high thermal conductivity, and low coefficient of thermal expansion. Diamond reinforced aluminum metal matrix composites were prepared using a pressureless metal infiltration process. The diamond particulates are coated with SiC prior to infiltration to prevent the formation of Al4C3, which is a product of the reaction between aluminum and diamond. The measured thermal conductivity of these initial diamond/Al metal matrix composites is as high as 259 W/m-K. The effects of coating thickness on the physical properties of the diamond/Al metal matrix composite, including Young's modulus, 4-point bend strength, coefficient of thermal expansion, and thermal conductivity, are presented.

The Minimum Representative Volume Element Size for Coefficient of Thermal Expansion of Particle Reinforced Metal Matrix Composites

2013 â—½  
Vol 773 â—½  
pp. 435-440
Author(s):  
X.X. Zhang â—½  
B.L. Xiao â—½  
Z.Y. Ma
Keyword(s):  
Thermal Expansion â—½  
Metal Matrix Composites â—½  
Metal Matrix â—½  
Coefficient Of Thermal Expansion â—½  
Three Dimensional â—½  
Analytical Models â—½  
Matrix Composites â—½  
Element Size â—½  
Representative Volume Element Size â—½  
Sharp Edges

A 3D realistic microstructure based computational homogenization model is proposed, in order to determine the temperature dependent effective coefficient of thermal expansion of particle reinforced metal matrix composites The model employed three-dimensional realistic microstructures with different domain sizes, where particles had random shape, sharp edges and were randomly distributed. The unit cell microstructure based model and classical analytical models were also presented for comparison. As an illustration of the model, a 17% vol. SiCpreinforced 2124Al composite was investigated. Its minimum RVE size is found to beδ= 15, whereδis called the size ratio and defined by the ratio between the side length of microstructure and the mean particle radius.

Coefficient of Thermal Expansion Measurement of Metal Matrix Composites by Thermo Mechanical Analyser

2011 â—½  
Vol 264-265 â—½  
pp. 663-668 â—½  
Author(s):  
B. Karthikeyan â—½  
S. Ramanathan â—½  
V. Ramakrishnan
Keyword(s):  
Thermal Expansion â—½  
Metal Matrix Composites â—½  
Metal Matrix â—½  
Coefficient Of Thermal Expansion â—½  
Stir Casting â—½  
Matrix Composites â—½  
Aerospace Materials â—½  
Casting Technique â—½  
Actual Use â—½  
The Matrix

The demand of today’s and future spacecrafts for a stable platform for critical payloads is the driving force behind the coefficient of thermal expansion (CTE) measurement of different aerospace materials. The CTE of a composite is different from that given by a simple rule of mixtures. This is because of the presence of reinforcement. The expansion coefficient of reinforcement is less than that of the matrix which introduces a mechanical constraint on the matrix. The degree of constraint is also dependent on the nature of the reinforcement. It is important to point out that interface can exert some influence on the value of CTE, especially for very small particle size. In addition to the interface, the CTE of particle reinforced metal matrix composites (MMCs) is affected by several other factors. To cater the needs of various requirements in a spacecraft making, a wide variety of materials are used. Besides, the indigenization efforts and development of new materials for space-use emphasizes the measurement of CTE before their actual use. Stir casting technique was used to fabricate composites containing Si Cp as reinforcements and special thermo physical properties of the material are found. CTE of the composites are measured by TMA. The experiments have been carried out in the temperature range -1400 C to 5750 C.

Computational investigation on thermal expansivity behavior of Al 6061–SiC–Gr hybrid metal matrix composites

2015 â—½  
Vol 04 (03) â—½  
pp. 1550016
Author(s):  
S. A. Mohan Krishna â—½  
T. N. Shridhar â—½  
L. Krishnamurthy
Keyword(s):  
Thermal Expansion â—½  
Metal Matrix Composites â—½  
Metal Matrix â—½  
Hybrid Composites â—½  
Coefficient Of Thermal Expansion â—½  
Thermal Expansivity â—½  
Matrix Composites â—½  
Computational Investigation â—½  
Al 6061 â—½  
Wide Range

Metal matrix composites (MMCs) have been regarded as one of the most principal classifications in composite materials. The thermal characterization of hybrid MMCs has been increasingly important in a wide range of applications. The coefficient of thermal expansion is one of the most important properties of MMCs. Since nearly all MMCs are used in various temperature ranges, measurement of coefficient of thermal expansion (CTE) as a function of temperature is necessary in order to know the behavior of the material. In this research paper, the evaluation of thermal expansivity has been accomplished for Al 6061, silicon carbide ( SiC ) and Graphite ( Gr ) hybrid MMCs from room temperature to 300°C. Aluminum ( Al )-based composites reinforced with SiC and Gr particles have been prepared by stir casting technique. The thermal expansivity behavior of hybrid composites with different percentage compositions of reinforcements has been investigated. The results have indicated that the thermal expansivity of the different compositions of hybrid MMCs decreases by the addition of Gr with SiC and Al 6061. Few empirical models have been validated for the evaluation of thermal expansivity of composites. Using the experimental values namely modulus of elasticity, Poisson's ratio and thermal expansivity, computational investigation has been carried out to evaluate the thermal parameters namely thermal displacement, thermal strain and thermal stress.

Effect of Thermal Stresses on the Thermal Expansion and Damping Behavior of ZA-27/Aluminite Metal Matrix Composites

2001 â—½  
Vol 10 (2) â—½  
pp. 220-224 â—½  
Author(s):  
Shanta Sastry â—½  
M. Krishna â—½  
Jayagopal Uchil
Keyword(s):  
Thermal Expansion â—½  
Metal Matrix Composites â—½  
Metal Matrix â—½  
Thermal Stresses â—½  
Matrix Composites â—½  
Damping Behavior

scholarly journals Wettability in Metal Matrix Composites

Metals â—½  
10.3390/met11071034 â—½  
2021 â—½  
Vol 11 (7) â—½  
pp. 1034
Author(s):  
Massoud Malaki â—½  
Alireza Fadaei Tehrani â—½  
Behzad Niroumand â—½  
Manoj Gupta
Keyword(s):  
Metal Matrix Composites â—½  
Metal Matrix â—½  
Aluminum Matrix â—½  
Interfacial Strength â—½  
High Strength â—½  
Aluminum Matrix Composites â—½  
Matrix Composites â—½  
Metal Matrix Nanocomposites â—½  
Aerospace Applications â—½  
Matrix Nanocomposites

Metal matrix composites (MMCs) have been developed in response to the enormous demand for special industrial materials and structures for automotive and aerospace applications, wherein both high-strength and light weight are simultaneously required. The most common, inexpensive route to fabricate MMCs or metal matrix nanocomposites (MMNCs) is based on casting, wherein reinforcements like nanoceramics, -carbides, -nitrides, elements or carbon allotropes are added to molten metal matrices; however, most of the mentioned reinforcements, especially those with nanosized reinforcing particles, have usually poor wettability with serious drawbacks like particle agglomerations and therefore diminished mechanical strength is almost always expected. Many research efforts have been made to enhance the affinity between the mating surfaces. The aim in this paper is to critically review and comprehensively discuss those approaches/routes commonly employed to boost wetting conditions at reinforcement-matrix interfaces. Particular attention is paid to aluminum matrix composites owing to the interest in lightweight materials and the need to enhance the mechanical properties like strength, wear, or creep resistance. It is believed that effective treatment(s) may enormously affect the wetting and interfacial strength.

Thermal expansion characteristics of cast Cu based metal matrix composites

1997 â—½  
Vol 28 (12) â—½  
pp. 1019-1022 â—½  
Author(s):  
K. Prakasan â—½  
S. Palaniappan â—½  
S. Seshan
Keyword(s):  
Thermal Expansion â—½  
Metal Matrix Composites â—½  
Metal Matrix â—½  
Matrix Composites

Production of Al Metal Matrix Composites by the Stir-Casting Method

2013 â—½  
Vol 592-593 â—½  
pp. 614-617 â—½  
Author(s):  
Konstantinos Anthymidis â—½  
Kostas David â—½  
Pavlos Agrianidis â—½  
Afroditi Trakali
Keyword(s):  
Mechanical Properties â—½  
Metal Matrix Composites â—½  
Automobile Industry â—½  
Metal Matrix â—½  
Aluminum Matrix â—½  
Stir Casting â—½  
Aluminum Matrix Composites â—½  
Matrix Composites â—½  
Casting Method â—½  
Alloy Matrix

It is well known that the addition of ceramic phases in an alloy e.g. aluminum, in form of fibers or particles influences its mechanical properties. This leads to a new generation of materials, which are called metal matrix composites (MMCs). They have found a lot of application during the last twenty-five years due to their low density, high strength and toughness, good fatigue and wear resistance. Aluminum matrix composites reinforced by ceramic particles are well known for their good thermophysical and mechanical properties. As a result, during the last years, there has been a considerable interest in using aluminum metal matrix composites in the automobile industry. Automobile industry use aluminum alloy matrix composites reinforced with SiC or Al2O3 particles for the production of pistons, brake rotors, calipers and liners. However, no reference could be cited in the international literature concerning aluminum reinforced with TiB particles and Fe and Cr, although these composites are very promising for improving the mechanical properties of this metal without significantly alter its corrosion behavior. Several processing techniques have been developed for the production of reinforced aluminum alloys. This paper is concerned with the study of TiB, Fe and Cr reinforced aluminum produced by the stir-casting method.

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