【摘要】 利用XRD,SEM,EDS及TEM对TiAl/TiB2复合材料在静止空气中高温氧化后的氧化膜结构及其形成机制进行了研究。结果表明:TiAl/TiB2复合材料的氧化膜主要由TiO2外层与由TiO2和Al2O3混合内层构成。TiO2和Al2O3混合内层为孔洞较多的疏松状结构。TiO2外层亦可分为内外两层,TiO2的内层部分存在一些与TiB2的轮廓相似的“孔洞”,TiO2的外层部分没有此类孔洞。由于TiAl/TiB2复合材料中的TiB2被氧化后生成的B2O3在高温下蒸发掉,使氧化膜中TiB2所处的位置留下了孔洞。因此,氧化膜中的部分孔洞是由于TiB2被氧化后产生的;氧化温度达到1000℃时,TiAl/TiB2复合材料中的TiB2使氧化膜中的孔洞数量增加,复合材料的抗氧化性能急剧下降。更多还原

【Abstract】 The structure and formation mechanism of oxide scale of TiAl/TiB2 composites at 1000℃ in static air were investigated by XRD, SEM, EDS and TEM. The results show that the oxide scale of TiAl/TiB2 composites include an outer layer mainly consisting of TiO2 grains and an inner porous layer which is the mixture of TiO2 and Al2O3 grains. And TiO2 outer layer is composed of an outer compact layer and an inner layer with pores similar to the shape of TiB2. As the B2O3 resulted from oxidized TiB2 evaporate at the oxidation temperature, TiB2 in the alloys increase the ratio of pores in oxide scale, and some of the pores in oxide scale is come from oxidation of TiB2.The oxidation resistance of TiAl/TiB2 composites dropped highly when oxidation temperature is higher than 1000℃.更多还原