Study and investigation on the formation of NbAl3-based nanocomposite reinforced by Al2O3 particles: microstructural and thermal analysis investigation

The aim of this research is fabrication of NbAl3-based nanocomposite via mechanical alloying in order to increase its toughness and high-temperature strength. For this purpose, mixtures of 49 wt.% of aluminum and 51 wt.% of niobium oxides were mixed and mechanically alloyed. Phase evolutions, microstructure and morphology of powder particles during milling were studied using X-ray diffractometry (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In order to study the thermal behavior of powder particles, annealing treatment and differential thermal analysis (DTA) were carried out. It was found that the reaction between aluminum and niobium oxide is explosive and during this reaction NbAl3-based nanocomposite reinforced by Al2O3 particle is formed. The as-blended powders were studied by DTA and the results showed that in this condition NbAl3/Al2O3 composite is formed within two stages. At the first step, Nb2O5 is reduced by aluminum. At the second step, the retained aluminum is reacted by niobium and finally NbAl3/Al2O3 composite is formed. Observations by TEM revealed formation of nanostructure and nano-sized reinforcement particles.