原位自生成TiC/Ti基复合材料的高温氧化  

Oxidation Behaviors of In-Situ TiC/Ti Alloy Composite at High Temperatures

作　　者：张小农[1] 李超[1] 李小璀[1] 何利舰[1] 

机构地区：[1]上海交通大学,上海200030

出　　处：《稀有金属材料与工程》2004年第3期258-261,共4页Rare Metal Materials and Engineering

摘　　要：利用热重分析(TGA)测量了原位生成的TiC/Ti-6Al复合材料在600,700和800℃下经连续20 h的氧化增重特性,利用SEM, EDS和XRD研究了复合材料经氧化试验后表面氧化层的结构,相组成及成分。结果表明,原位生成的Ti基复合材料在高温氧化时遵循抛物线规律在800℃时的氧化增重量远大于600℃和700℃时的,计算获得该复合材料的氧化激活能为255.7 kJ/mol。研究发现经20 h的600℃或700℃氧化形成的氧化物呈现不连续的岛屿状,主要成分为金红石型的TiO2,而在800℃氧化20 h后,氧化物是均匀连续的致密膜,由TiO2,Al2O3组成。该复合材料的氧化首先发生在TiC颗粒的表面上,而不是象均质Ti材料一样氧化在整个表面上均匀地发生。Oxidation behaviors of in-situ synthesized TiC/Ti-6Al metal matrix composite were studied by using TGA to achieve the continuous weight gain at 600degreesC, 700degreesC and 800degreesC for 20 hours, respectively. Then SEM, XRD and EDS were used to detect the microstructures and the compositions of the oxidized scales. The experimental results show that the in-situ TiC/Ti-6Al composite oxidized at high temperatures basically follows a parabolic rule. The weight gain when oxidized at 800degreesC is much more than that at 600degreesC and 700degreesC. The activation energy for oxidation of in-situ Ti matrix composite is calculated to be 255.7 kJ/mol. Furthermore, based on the microstructural researches, it is found that the oxides consists of rutile TiO2 and is not continuous on the surface when oxidized at 600degreesC and 700degreesC for 20 hours. However, the oxides at 800degreesC for 20 hours are dense and continuous and consist of TiO2 and Al2O3, It is concluded that the oxidation of the composite material occurs firstly on the surfaces of TiC particulates, not as the homogeneous materials in which the oxidation always happens on the whole surface uniformly.

关 键 词：钛基复合材料 原位自生成 热重分析 氧化增重特性 氧化激活能 TiC/Ti-6Al复合材料 

分 类 号：TB331[一般工业技术—材料科学与工程]