摘要
热重分析法(TGA)测量了原位合成不同碳化物含量的钛基复合材料,在900℃连续60 h高温氧化后的氧化增重特性。利用SEM、EDS和XRD研究了复合材料氧化后氧化膜表面和横断面的结构、相组成和成分。结果表明,复合材料的氧化动力学曲线介于抛物线和对数规律之间;随着复合材料中碳化物含量的增加,氧化膜的厚度逐渐减小,即抗氧化性逐渐增强。表层氧化膜主要为堆砌生长的柱状六方晶,氧化膜横断面为明暗交替的多层结构。基体合金的最内层氧化膜为形状比较规则的柱状晶,而复合材料的最内层氧化物则是在碳化物颗粒的周围产生的,说明钛基复合材料的氧化首先发生在碳化物颗粒的表面及周围,而不是像均质钛材料一样在整个表面均匀地发生氧化。
Oxidation behaviors of in-situ synthesized Ti matrix composites with different carbide contents were studied by using TGA to achieve the continuous weight gain at 900℃ for 60 hours. Then SEM, EDS and XRD were used to detect the microstructures and the compositions of the surface and cross-section oxidized scales. The results show that the isothermal oxidation kinetic curves of composites follow the law between parabolic rate law and logarithmic rate law. The oxidation resistance of composites increases with increasing carbide content to a certain extent. The surface morphology is mainly made of columnar hexagonal grains which grow compactly, while the cross-section morphology is the structure of alternating growth. For matrix alloy, the oxidized scale of inner layer is made of columnar hexagonal grains with regular shapes. However, the inner layer oxidized scales of the composites occur around the carbide particles. It is concluded that the oxidation of the composite material occurs firstly on the surfaces and periphery of carbide particles, not as the homogeneous materials in which the oxidation always happens on the whole surface uniformly.
出处
《铸造技术》
CAS
北大核心
2010年第7期860-864,共5页
Foundry Technology
关键词
钛基复合材料
氧化动力学
抗氧化性
显微结构
Titanium matrix composite
Oxidation kinetics Oxidation resistance
Microstructure
