Thermal Expansion Measurements of Metal Matrix Composites

2009 ◽  
pp. 248-248-11 ◽  
Author(s):  
SS Tompkins ◽  
GA Dries
Keyword(s):  
Thermal Expansion ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Matrix Composites

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

2000 ◽  
Author(s):  
Fuat Okumus ◽  
Aydin Turgut ◽  
Erol Sancaktar
Keyword(s):  
Thermal Expansion ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Thermal Stresses ◽  
Coating Layer ◽  
Coefficient Of Thermal Expansion ◽  
Aluminum Matrix ◽  
Matrix Composites ◽  
Cylinder Model ◽  
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 ◽  
Vol 8 (5) ◽  
pp. 1169-1173 ◽  
Author(s):  
William B. Johnson ◽  
B. Sonuparlak
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Coefficient Of Thermal Expansion ◽  
Matrix Composites ◽  
Infiltration Process ◽  
Point Bend ◽  
Aluminum Metal Matrix Composites ◽  
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.

scholarly journals Measurement of Residual Stresses in Metal Matrix Composites

1993 ◽  
Author(s):  
P. K. Wright
Keyword(s):  
Thermal Expansion ◽  
Residual Stresses ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Stress Measurement ◽  
Fiber Direction ◽  
Matrix Composites ◽  
Thermal Expansion Coefficients ◽  
The Matrix

Metal matrix composites (MMC) are expected to develop internal residual stresses on cooling from fabrication due to the large thermal expansion mismatch between reinforcing fibers and the matrix. This work was undertaken to experimentally measure these residual stresses and compare them with analytical calculations in order to clearly establish their levels and dependence on material parameters. Two techniques for residual stress measurement were investigated: 1) Xray diffraction (sin2 psi method) and 2) neutron diffraction. Both techniques gave results in good agreement with analytical predictions for several systems (SCS-6/Ti-24Al-11Nb, W/NiAl, and Al2O3NiAl). The results obtained showed a dependence of residual stresses on thermal expansion coefficients, elastic moduli, volume fraction fibers, and matrix yield strengths. The fibers showed compressive stress states, and the matrix, tension. Average stresses were higher in the fiber direction than transverse to fibers.

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