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材料研究学报 2004
Effect of vacuum thermo--cycling on mechanical properties of M40J/epoxy composites
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Abstract:
The vacuum thermo--cycling(93$\sim$413 K, 10$^{-5}$Pa) was performed on unidirectional M40J/5228A composites, and the 90$^{\circ}$ and 0$^{\circ}$ tensile strengths, bend strength and interlayer strength were examined after vacuum thermo-cycling for various cycles. The fracture of surfaces of the specimens was observed by SEM. The influence of vacuum thermo--cycling on the mechanical properties of the M40J/5228A composites was investigated. The results show that with increasing the thermal cycles, both the 90$^{\circ}$ and 0$^{\circ}$ tensile strengths decrease and tend to level off after the cycles of 48 and 40, respectively. The bend strength shows a trend of ascending followed by descending and leveling off, while the interlayer strength do not change a lot. The changes of the 90$^{\circ}$ and 0$^{\circ}$ tensile strengths could be related to the interface debonding. The thermo--cycling would cause additional curing of the epoxy matrix and affect the bent strength. The change in the interlayer strength depends on the combination of the interface debonding and the followed curing caused by the vacuum thermo--cycling.
