原位反应制备从Al_2O_3颗粒增强铝基复合材料

In-Situ Process in Al-TiO_2-B_2O_3 System During Synthesis of Particle-Reinforced Aluminum Matrix Composite by Differential Scanning Calorimetry

利用差分扫描热分析研究了利用Ａｌ－Ｎｂ２Ｏ５系统制备Ａｌ２Ｏ３颗粒增强金属基复合材 料这的原位反应过程：用Ｘ－射线衍射分析了反应过程中的相变．实验结果表明，Ｎｂ 的还原和ＮｂＡｌ３金属间化合物的形成反应发生在Ａｌ的熔点以下；在９３９℃完成．在低温 下，试样的局部发生少量的原位反应；整个试样内部同时发生原位反应是在９３９℃放热峰 所覆盖的温度区间．最终显微组织中存在相同形态不同尺寸的ＮｂＡｌ３相．低温形成的 ＮｂＡｌ３相由于经历了长大过程而尺寸较大；高温形成的ＮｂＡｌ３相尺寸较小．

The in-situ process of alumina particles and niobium aluminide in aluminum matrix composite, using Al-20wt% Nb2O5 system, has been studied by means of differential thermal analysis together with X-ray diffraction analysis. The reduction of Nb from its oxide and the formation of NbAl3, start below the melting point of aluminum. The bulk in-situ reactions in the system occurs between 920 ℃ and 940 ℃. There are two kinds of NbAl3 phase with the same morphology and different size in the final structure of the Al-Nb2O5 system. The ones formed at lower temperature has grown into larger blocks, while the ones formed at higher temperature remain smaller.