Formation of Ti-Al Phases during SHS Process

TiAl alloys are promising materials for aircraft industry and they could be produced by self-propagating high-temperature synthesis. This method should replace the melt-metallurgy processes which are often used in their production. However, a lot of intermediary phases which are usually unwanted form during this process and therefore parameters of their formation during self-propagating high-temperature synthesis should be determined. Unfortunately, many reaction conditions influence whole process. In this work, one of these parameters - a heating rate - was studied by two methods of thermal analysis (differential thermal analysis and using an optical pyrometer). It was revealed that increase of heating rate moves the exothermic peaks to higher temperatures and the same phases form in all cases. All exothermic reactions are probably associated with the formation of TiAl phase. Real self-propagating high-temperature synthesis reaction was also performed at the lowest and the highest heating rate for comparison.