Morphological optimization of process parameters of randomly oriented carbon/carbon composite
관리자2014-02-04조회 5175
A microstructure analysis is carried out to optimize the process parameters of a randomly
oriented discrete length hybrid carbon fiber reinforced carbon matrix composite. The composite
is fabricated by moulding of a slurry into a preform, followed by hot-pressing and
carbonization. Heating rates of 0.1, 0.2, 0.3, 0.5, 1, and 3.3°C/min and pressures of 5, 10, 15,
and 20 MPa are applied during hot-pressing. Matrix precursor to reinforcement weight ratios
of 70:30, 50:50, and 30:70 are also considered. A microstructure analysis of the carbon/
carbon compacts is performed for each variant. Higher heating rates give bloated compacts
whereas low heating rates give bloating-free, fine microstructure compacts. The compacts
fabricated at higher pressure have displayed side oozing of molten pitch and discrete length
carbon fibers. The microstructure of the compacts fabricated at low pressure shows a lack of
densification. The compacts with low matrix precursor to reinforcement weight ratios have
insufficient bonding agent to bind the reinforcement whereas the higher matrix precursor to
reinforcement weight ratio results in a plaster-like structure. Based on the microstructure
analysis, a heating rate of 0.2°C/min, pressure of 15 MPa, and a matrix precursor to reinforcement
ratio of 50:50 are found to be optimum w.r.t attaining bloating-free densification
and processing time.
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