The effects of cold deformation on the morphology of c( precipitates were examined fo~three f3 titanium ailoys which were each mainly deformed by slip On the other hand, there wasno significant difference reflected by the initial deformation modes in the oc morphology after heavy deformation (60"/• rolling) among the three alloys, and the microstructures were considered to be of a microdupiex structure,

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Quenchedmicrostructures of Til 6V-1Sn-3Al, Ti-1 6V~SSnlAl, and Ti1 6V~Sn3Al. X-ray profiles of the 3 o/, cold rolled samples for (a) Ti-1 6V-5Al andTi-1 6V7Al, and (b) Ti-1 8V-3Al and Ti22V3Al.

Fundam~ental study of the high temperature deformation of titanium aluminide. TiAl, has been conducted in order to develop the manufacturing process using isothermal forging. Theflow stress was exactly expressed using Zenner-Hollomon parameter as well as common metals. The recrystallization occurred during high temperature deformation, and structure was transformed from the lamellar structure to the fine recrystallized grain structure. And there were some deformation conditions where TiAl could be deformed without any defects up to 800/0 degree of reduction from as cast state.On the basis of above information. manufacturing of pancakes was carried out by isothermal forging. It was confirmed that it was possible to work plastically even from cast ingots samples and that mechanical properties could be improved by isothermal forging.These results suggest that the isothermal forging is a extremely effective process for manufacturing processes of TiAi.