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采用真空袋-热压罐工艺制备单向碳纤维增强树脂基复合材料(CFs/EP)层合板,并将高低温试验箱与万能试验机相结合,通过合理使用低温胶和低温引伸计,并在降温过程中实施应力应变实时调零等关键技术,在室温和液氧超低温度(-183℃)下对单向CFs/EP层合板进行拉伸和弯曲试验,研究了其超低温力学性能,并根据室温和超低温试验后试样的微观和宏观特征,揭示了超低温环境下复合材料力学性能变化机制。结果表明,与室温力学性能相比,单向CFs/EP层合板超低温拉伸强度下降约为9.5%,而拉伸模量上升约为6.2%,主要是由于超低温环境下,树脂的收缩使绝大部分碳纤维与树脂间形成了强界面,拉伸后试样呈“劈裂式”破坏形式,无法使每根纤维都充分发挥其强度,拉伸强度下降,同时超低温也限制了树脂大分子链的运动,所以导致单向CFs/EP层合板拉伸模量上升;单向CFs/EP层合板超低温弯曲强度和弯曲模量分别提高为约54.75%和11.64%,这是因为单向CFs/EP层合板的常温和超低温的弯曲破坏形式均为分层剪切破坏,超低温下复合材料的界面增强,提高了单向CFs/EP层合板抵抗剪切分层的能力,进而使CFs/EP的弯曲性能得到提高。
The unidirectional carbon fiber reinforced resin matrix composite (CFs / EP) laminates were prepared by the vacuum bag-autoclave process. The high and low temperature chambers were combined with the universal testing machine. Through the reasonable use of low temperature glue and low temperature extensometer, Key technologies such as real-time zeroing and stress-strain during cooling were researched. The uniaxial CFs / EP laminates were subjected to tensile and bending tests at room temperature and ultra-low temperature of liquid oxygen (-183 ℃), and their mechanical properties at low temperature were studied. The microscopic and macroscopic characteristics of the samples after room temperature and ultra-low temperature tests reveal the mechanism of the mechanical properties of the composite under ultra-low temperature. The results showed that the tensile strength of unidirectional CFs / EP laminates decreased by about 9.5% at room temperature and tensile modulus increased by about 6.2% compared with that at room temperature, which was mainly due to the shrinkage of the resin at ultra-low temperature Most of the carbon fiber and resin to form a strong interface between the tensile specimen after the sample was “split” type of destruction, can not make each fiber give full play to its strength, tensile strength decreased, while ultra-low temperature also limits the resin macromolecular chains , The tensile modulus of unidirectional CFs / EP laminates increased. The uniaxial CFs / EP laminates increased their flexural strength and flexural modulus by about 54.75% and 11.64%, respectively, because of the unidirectional CFs / EP At room temperature and ultra-low temperature, the bending failure modes of laminates are both layered shear failure and the interface of composite material is enhanced at ultra-low temperature, which improves the ability of unidirectional CFs / EP laminates to resist shear stratification, Performance is improved.