摘要
本文制备了短碳纤维长度为7mm的预制体,然后再与铝硅酸盐聚合物配合料复合制备了纤维含量分别为3.5vol%、4.5vol%和6.0vol%的短碳纤维强韧的铝硅酸盐聚合物基复合材料。通过对复合材料三点弯曲力学性能测试以及测试过程中试样拉伸侧面微观裂纹的原位观察,对复合材料的力学性能,韧化机理以及断裂行为进行了研究。研究发现,纤维的加入极大的改善了复合材料的强度和韧性并使复合材料呈现"伪塑性"断裂特征。原位观察表明,弯曲测试过程中复合材料拉伸面会产生大量的次生裂纹并逐步扩展。随着载荷达到最大值,主裂纹产生并导致次生裂纹处应力出现下降,致使次生裂纹扩展停滞并呈现一定程度的闭合。复合材料拉伸面次生裂纹的萌生及扩展是复合材料具有较大断裂功的主要原因。随着复合材料模量的增加,复合材料拉伸面次生裂纹的扩张幅度逐步缩小,变形能力减弱。
Geopolymer matrix composites reinforced by 3.5vo1%, 4.5vo1% and 6.0vol% short carbon fiber were prepared by mixing the pre-prepared performs have a short carbon fiber length in 7 mm with geopolymer resin. The mechanical properties, toughening mechanism and fracture behavior of the obtained composites were studied by three-point flexural test and in-situ scanning electron microscopy. The results show flexural strength and toughness of the composites have an apparent improvement than that of the geopolymer matrix, and the composites show a typical pseudoplastieity behavior. In-situ observations show a lot of microcracks generate and extend homogeneously on the tensile side of the composites. The main crack gradually extends and results in the stress on the minor cracks are released with the maximum load is reached, so the propagation of the minor cracks ceases, and these cracks tend to close to some extent. The propagation and extension of the minor cracks on the tensile side of the composites are the main reasons for the higher work of fracture. With the increase of the modulus of the composites, the extension of the minor cracks is decreased gradually, and deformation ability of the composites is weakened.
出处
《硅酸盐通报》
CAS
CSCD
北大核心
2010年第2期278-283,共6页
Bulletin of the Chinese Ceramic Society
关键词
铝硅酸盐聚合物
短碳纤维
原位观察
强韧化机理
断裂行为
geopolymer
short carbon fiber
in-situ observation
strengthening/toughening mechanism
fracture behavior
