THE FORMATION OF TI3AL WITHIN TIAL DURING THE DEFORMATION OF XDTM TITANIUM ALUMINIDE

The materials used were Ti-45Al/TiB2, initially produced by Martin Marietta Laboratory through XDTM processing, followed by casting and extrusion at 1200°C. The extrusion ratio was 3.5:1. Transmission electron microscopy(TEM) foils of as-cast and as-extruded materials were prepared. A mechanism involving the formation of TiAlSF can explain how Ti3Al layers and TiAlT can be formed within TiAl during deformation. This mechanism is similar to that previously suggested for the formation of TiAlM/TiAlT laths which initiate at Ti3AlSF during the ordering transformation of Ti3Al and can be applied to the formation of TiAlM/TiAlT during deformation processing of Ti3Al.