真空热循环对M40J/环氧复合材料力学性能的影响

Effect of vacuum thermo-cycling on mechanical properties of M40J/epoxy composites

分别测量了经不同次数单向真空热循环试验(93～413 K,10^(-5)Pa)后M40J/5228A复合材料的拉伸强度、弯曲强度和层剪强度,研究了真空热循环对M40J/环氧复合材料力学性能的影响。结果表明,随着真空热循环次数的增加,90°和0°拉伸强度下降,并分别于48次和40次真空热循环后趋于平缓。弯曲强度随着真空热循环次数的增加表现出先上升后下降再趋于平缓的特征,而层剪强度变化不大。90°和0°拉伸强度的变化与界面脱粘程度密切相关。弯曲强度变化主要反映真空热循环时树脂基体后续固化效应的影响。层剪强度变化是界面脱粘与树脂基体后续固化两种因素综合作用的结果。

The vacuum thermo-cycling (93-413 K, 10-5 Pa) was performed on unidirectional M40J/5228A composites, and the 90° and 0° 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° and 0° 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° and 0° tensile strengths could be related to the interface debonding. The thermo-cycling would cause additional curing of the epoxy matrix and affect the bend 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.