Elasticity and inelasticity of biomorphic carbon,silicon carbide,and SiC/Si composite produced on the basis of medium density fiberboard |
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Authors: | B K Kardashev T S Orlova B I Smirnov A R de Arellano-Lopez and J Martinez-Fernandez |
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Institution: | 1.Ioffe Physical-Technical Institute,Russian Academy of Sciences,St. Petersburg,Russia;2.Universidad de Sevilla,Sevilla,Spain |
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Abstract: | The amplitude and temperature dependences of the Young’s modulus and the internal friction (ultrasonic absorption) of biomorphic
carbon, silicon carbide, and SiC/Si composite produced from medium density fiberboard (MDF) by pyrolysis (carbonization),
followed by infiltration of molten silicon into the prepared carbon preform have been studied in the temperature range 100–293
K in air and under vacuum. The measurements have been performed by the acoustic resonance method with the use of a composite
vibrator for longitudinal vibrations at frequencies of approximately 100 kHz. The data obtained by acoustic measurements of
the amplitude dependences of the elastic modulus have been used for evaluating the microplastic properties of samples under
study. It has been shown that the Young’s modulus, the decrement of elastic vibrations, and the conventional microyield strength
of the MDF samples differ from the corresponding data for previously studied similar materials produced from natural eucalyptus,
beech, sapele, and pine woods. In particular, the desorption of environmental molecules at small amplitudes of vibrations,
which is typical of biomorphic materials based on natural wood, is almost absent for the MDF samples. The results obtained
have been explained by different structures and the influence of pores and other defects, which, to a large extent, determine
the mechanical characteristics of the biomaterials under investigation. |
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