碳纤维表面改性增强Fe3Al-Al2O3复合材料的制备及组织性能

《复合材料学报》优先在线发表论文。

摘  要：采用溶胶-凝胶分散和热压烧结制备了CFs/Fe3Al-Al2O3复合材料。分别通过电化学镀Cu和化学气相沉积PyC-SiC对短切碳纤维(CFs)表面修饰和改性，研究了Cu镀层和SiC涂层对CFs/Fe3Al-Al2O3复合材料显微组织、相组成、力学性能及断裂行为的影响。结果表明，未修饰的CFs在Fe3Al-Al2O3基体中受到严重侵蚀，复合材料致密度低，抗弯强度仅为239.0MPa，与Fe3Al-Al2O3强度相当；表面镀Cu可有效保护碳纤维不被侵蚀，同时提高了复合材料的烧结致密性和界面结合强度，从而明显提高材料的断裂强度，但断裂过程中纤维拔出较短；碳纤维表面沉积SiC的CFs/Fe3Al-Al2O3复合材料组织均匀致密，表面涂层完整，且与纤维及基体之间结合力相当，断裂过程中，涂层既可随纤维一起拔出基体，也可与碳纤分离而留在基体之中，SiC涂层与纤维及基体之间的弱相互作用很大程度上促进了纤维脫粘与拔出，从而促进复合材料韧化所需的渐进破坏机制。

关键词：陶瓷基复合材料；碳纤维；Al2O3；Fe3Al

Abstract: The CFs/Fe3Al-Al2O3 composites were prepared by a sol-gel dispersing method and a subsequent hot-pressing process. Cu coating and SiC coating applied to short carbon fiber (CFs) were fabricated by electrochemistry and in-situ reaction method, respectively. The effects of Cu coating and SiC coating applied to carbon fiber on the microstructure, phase composition, mechanical properties and fracture behavior of CFs/Fe3Al-Al2O3 composites were investigated. The results showed that composites fabricated from the as-received CFs exhibit low density and the flexural strength is only 239 MPa comparable with matrix due to the carbon fiber severely eroded in Fe3Al-Al2O3 matrix. Cu coating applied to carbon fiber can effectively protect carbon fiber eroded by matrix, improve sintering compactness and cause strong bonding between the fiber and matrix that cause high flexural strength, however, the length of fibers extending from the matrix are short during the fracture process. Composites fabricated from SiC coating exhibited homogeneous microstructure, the coating onto fiber integrated and soft bonding between fiber and matrix which result fiber with SiC coating extending from matrix or SiC coating remained in the pull-out holes. The weak interaction between the fiber with SiC coating and matrix greatly promotes fiber debonding and extending from matrix to promote toughening and progressive failure mechanisms in the composites.

Keywords:  ceramic-matrix composites; carbon fiber; Al2O3; Fe3Al

作者：贾建刚等，兰州理工大学 甘肃省有色金属新材料国家重点实验室，兰州

通讯作者：贾建刚，兰州理工大学 甘肃省有色金属新材料国家重点实验室，兰州

全文详见中国知网学术期刊优先数字出版。