【摘要】 在N₂气氛下用热压烧结方法,在TiCN-NbC-Mo₂C-Ni基质中添加聚丙烯腈预氧化纤维（PAN）作为先驱体原位热解成碳纤维,成功制备得到了组成均匀的Ti CN基金属陶瓷,并研究了PAN添加量（0²5 vol%）对所制备金属陶瓷的微观结构及力学性能的影响。X射线衍射分析表明,随着PAN添加量的增多,热解产生的石墨相含量越来越高;当PAN添加量为25 vol%时,观察到明显的石墨相（002）衍射峰。用扫描电子显微镜在金属陶瓷的断口观察到了韧性窝、撕裂棱及纤维拔出等现象;而在纤维状物质表面上进行的能谱分析表明,其碳原子含量达到90.9 at%以上,说明PAN预氧化纤维热解成了碳纤维。实验表明,随着PAN添加量的增加,所得金属陶瓷的密度和相对密度均逐渐减小;硬度逐渐降低;而抗弯强度和断裂韧性都先增大后减小,当PAN添加量为15 vol%时其抗弯强度达到最大值（约为1020MPa）,当PAN添加量为20 vol%时其断裂韧性达到最大值（约10.8 MPa·m1/2）。更多还原

【Abstract】 TiCN-NbC-Mo₂C-Ni cermets with different amounts of pre-oxidized polyacrylonitrile precursor fibers（PAN）（0²5 vol%） were fabricated by hot-pressing sintering under N₂. The addition effect of PAN on the microstructure and mechanical properties of the obtained samples was investigated. XRD analysis shows that the composites present an apparent diffraction peak at 26.3°, corresponding to（002） crystal face of carbon fibers, when the fraction of PAN reaches 25 vol%. EDX analysis reveals that the carbon content of the transformed fibers is 90.9 at%, confirming the transformation of the PAN precursor fibers to carbon ones during the design sintering process. Scanning electron microscopy examination indicates that dimples, torn edges and pulling out of the fibers happen during the fracture of the cermets. With increasing addition fraction of PAN, the flexural strength and fracture toughness of the cermets first increase and then decrease. When the added fraction of PAN is 15 vol%, the flexural strength reaches its maximum of about 1020 MPa. When the added fraction of PAN is 20 vol%, the fracture toughness reaches its maximum of about 10.8 MPa·m^1/2. Both the hardness and relative density of the cermets decrease with increasing addition fraction of PAN.更多还原