摘要
采用添加剂热压烧结制备了短纤维增韧氮化硅基复合材料,并对材料的力学性能和微观结构进行了分析和讨论。结果表明:Y2O3-La2O3添加剂促进了α-Si3N4→β-Si3N4的相转变,这个体系经过1800℃的热压烧结后,其中的碳纤维产生退化。而经过1600℃热压烧结的含LiF-MgO-SiO2添加剂的体系中,纤维保持完好,晶粒没有发生相转变。两个体系的复合材料的断裂韧性值均高于氮化硅基体的值,其提高幅度均接近20%,这归因于纤维拉拔、裂纹偏转和界面松解机制。
Ceramic matrix composites were prepared by hot pressing with Si3N4 powder, short carbon fiber and sintering additives. Their microstructure and mechanical properties were studied and discussed. La2O3-Y2O3 additives play a positive role in the transformation of a to β phase. And the degradation of carbon fiber occurs after sintering at 1800 ℃. After sintering at 1600 ℃, the phase transformation does not be detected. And the carbon fibers still keep their nature morphology in the LiF-MgO-SiO2 system. The ceramic matrix composites have the maximum value of the fracture toughness approximately by 20% higher than that of the monolithic silicon nitride in the two systems, which attribute to different toughness mechanisms： fiber pullout, flaw deflection and interfacial debonding.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2009年第A02期544-546,共3页
Rare Metal Materials and Engineering
关键词
微观结构
力学性能
复合材料
添加剂
microstructure
mechanical properties
composites
additives
