Theoretical and Experimental Research on Preparation of Ti-Al Alloy by Electric Aluminothermic Reduction

Ti-Al alloy was prepared using electric aluminothermic reduction method with titanium white as raw materials.The influence of temperature and aluminum addition on the alloy-slag separation,phase of slag,microstructure,composition and phase of alloy were researched.Through theoretical analysis it shows that the elevated roasting temperature can lower the viscosity of slag in favor of the alloy-slag separation.A better separation of alloy and slag can be obtained at 1 550 ℃ according to the experiments.Addition amount of aluminium has significant influence on the compositions of alloy and slag.The melting point and viscosity of slag increase with presence of massive low-valence titanium oxides in the slag caused by insufficient aluminium addition,and the slag-alloy separation is favorable with Al/TiO₂＞0.7.Increasing the aluminum addition can enhance the yield rate of alloy and titanium.Meanwhile,the aluminium content in Ti-Al alloy increases and the alloy phases convert.The main phases of alloy are TiAl and Ti₃Al as Al/TiO₂= 0.7 while TiAl and TiAl₃ as Al/TiO₂= 0.9.SEM,XRD and EDS analysis show that the slag included in alloy exists as CaAl₄O₇.