以Ti、Al、TiO2及Al2O3为原料,制成预制体,通过石墨与Al2O3混合粉对预制体的覆埋实现气氛保护并进行热处理,使其原位合成Al2O3纤维增强Ti—Al金属间化合物复合材料。考察了Al2O3对材料断口形貌组织、物相成分的影响,并结合DTA进行了热力学分析。XRD表明,外加Al2O3后材料氮化严重,主晶相由Al3Ti变为AlN.SEM表明,材料基体周围分布大量纤维,稀释剂Al2O3的加入有利于纤维的生长及分布。
Ti-Al intermetallics composites reinforced with in situ Al2O3 fibers were synthesized by use of Al-Ti system oxidized partly. The element compositions and the fracture section of composites were studied by XRD and SEM. Thermodynamic analysis was discussed according to DTA. Results show that titanium and aluminum are nitrided seriously due to addition of alumina, chief crystalline phase turns from Al3Ti into A1N. Lots of Al2O3 fibers distribute in intercrystalline boundary, which is considered to be of important value for the mechanical capabilities. In addition, it is observed that alumina powders as diluent could have an important effect on the growth and distribution of alumina fibers.