电热载荷对碳纤维复丝拉伸性能的影响

由于复合材料具有组成多元、各向异性等特点,电热载荷作用下碳纤维复合材料内部的响应行为十分复杂。为了研究碳纤维复合材料的电热响应,首先采用自制电热损伤试验平台,测试了不同电流强度下碳纤维复丝试样的表面温度分布,获得了碳纤维复丝电阻随温度的变化规律,初步揭示了碳纤维复丝具有温敏效应。然后,考察了不同电流处理条件下碳纤维复丝拉伸强度、断裂伸长率和拉伸模量的变化规律,并运用SEM和FTIR对电流处理前后材料的形貌和微观结构变化进行了分析。研究结果表明:纤维在通电过程中的产热效应促进了基体的进一步固化,同时提高了复丝界面的粘结性能;然而,当电流强度过大时,复丝的拉伸强度会因纤维本体的损伤或基体及界面层的烧蚀破坏而降低,从而降低了碳纤维复合材料的性能。 

Effects of electric-thermal load on tensile properties of carbon fiber multifilaments

The response behaviors of the interior of carbon fiber composites under the effects of electric-thermal load were very complicated for the composites had the characteristics of composition complexity, anisotropy and so on. In order to investigate the electric-thermal response of carbon fiber composites, self-devised electric-thermal damage test device was adopted, the temperature distribution on the surface of carbon fiber multifilament specimens under different current intensities was tested and the changing rules of the resistance of carbon fiber multifilament versus temperature were obtained firstly, and carbon fiber multifilament which had temperature-sensitive effect was preliminarily revealed. Then, the changing rules of tensile strength, elongation at break and tensile modulus under different current treatment conditions were investigated, and the morphology and microstructure changing of the materials before and after current treatment were analyzed by SEM and FTIR. The investigation results indicate that the heating effects of fibers in the galvanization promote the further solidification of the matrix, and improve the interfacial adhesion property of multifilament at the same time. However, when the current intensity is too high, the tensile strength of multifilament will decrease for the damage of fibers themselves or ablative degradation on matrix and interface layer, thus reduce the properties of carbon fiber composites.