层厚对TiC-HfN/TiC-HfC层状陶瓷微观组织及力学性能的影响

Effects of Layer Thickness on Microstructure and Mechanical Properties of TiC-HfN/TiC-HfC Laminated Ceramics

以TiC为基体相、Hf N和HfC分别为各层的增强相、Ni和Co为金属相,利用微叠层装置进行叠层,采用真空热压烧结技术,在1500℃下制备了不同层厚的TiC-Hf N/TiC-HfC层状陶瓷,其层厚分别为0.25、0.30、0.35、0.40mm,研究了层厚对该材料微观组织和力学性能的影响。研究结果表明:在不同层厚下,材料的断口形貌基本相似,且晶粒的尺寸均在5μm左右;随着层厚的增大,材料的相对密度、硬度和抗弯强度先增大后减小,层面断裂韧度基本保持不变,而层间断裂韧度不断减小;当层厚为0.30 mm时,材料具有相对较好的综合力学性能,此时其硬度为(19.6±0.24)GPa、抗弯强度为(841.1±20) MPa、层面断裂韧度为(6.5±0.18)MPa·m^(1/2)和层间断裂韧度为(8.3±0.27)MPa·m^(1/2)。

TiC-HfN/TiC-HfC layered ceramics with different layer thicknesses,consisting of the TiC matrix phase,the HfN and HfC additives and the Ni and Co metal phases,were laminated by the micro-laminated device and then they were sintered at 1500℃by vacuum hot-pressing sintering technology.Their layer thicknesses were 0.25 mm,0.30 mm,0.35 mm and 0.40 mm,respectively.The effects of layer thickness on their microstructure and mechanical properties were investigated.The results show that their fracture morphologies are basically similar to each other,and their grain size is about 5μm.With the increase of the layer thickness,their relative density,hardness and flexural strength increase first and then decrease,the fracture toughness of their layer basically remains unchanged,and the fracture toughness of their interlayer decreases gradually.When the layer thickness is 0.30 mm,the ceramic has relatively good comprehensive mechanical properties:its hardness is(19.6±0.24)GPa,its flexural strength is(841.1±20)MPa,its layer fracture toughness is(6.5±0.18)MPa·m^(1/2) and its interlayer fracture toughness is(8.3±0.27)MPa·m^(1/2).