Production of Al-Ti Master Alloy by Aluminothermic Reduction Technique

Abstract

Aluminum-titanium master alloys were prepared with an aluminothermic reduction of titanium dioxide dissolved in cryolite (NaF/AlF₃ = 2.5 molar ratio)-alumina melts in the presence of aluminum. The effects of time, the concentration of the titanium dioxide and temperature were investigated by spectrophotometer, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Al-Ti alloys containing about 7.8 wt% Ti were prepared at T=1120 °C after 10-15 minutes reduction time. The results showed that the reduction reaction occurred very quickly, i.e., within a few minutes. It was found that the reduction product at room temperature was a master alloy composed of an aluminum matrix and a TiAl₃ intermediate phase with needle shape. The reduction product was in fact a composite.

Aluminum-titanium master alloys were prepared with an aluminothermic reduction of titanium dioxide dissolved in cryolite (NaF/AlF₃ = 2.5 molar ratio)-alumina melts in the presence of aluminum. The effects of time, the concentration of the titanium dioxide and temperature were investigated by spectrophotometer, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Al-Ti alloys containing about 7.8 wt% Ti were prepared at T=1120 °C after 10-15 minutes reduction time. The results showed that the reduction reaction occurred very quickly, i.e., within a few minutes. It was found that the reduction product at room temperature was a master alloy composed of an aluminum matrix and a TiAl₃ intermediate phase with needle shape. The reduction product was in fact a composite.

On a préparé des alliages-mères d'aluminium-titane par réduction aluminothermique du dioxyde de titane dissout dans la cryolithe (NaF/AlF₃ = rapport molaire de 2.5)-bains d'alumine en présence d'aluminium. On a étudié les effets de la durée, de la concentration de dioxyde de titane et de la température au moyen des techniques de spectrophotométrie, de microscopie électronique à balayage (SEM) et de diffraction des rayons X (XRD). On a préparé un alliage d'Al-Ti contenant environ 7.8% en poids de Ti à T = 1120 °C après une durée de réduction de 10-15 minutes Les résultats montrent que la réaction de réduction s'est produite très rapidement, i.e. dans à peine quelques minutes. On a trouvé que le produit de réaction à la température de la pièce était un alliage-mère composé d'une matrice d'aluminium et d'une phase intermédiaire de TiAl₃ en forme d'aiguille. Le produit de la réduction était en fait un composite.