Thermo-mechanical processing of high-performance Ti alloys: recent progress and future needs

Over the past 10-15 years, improved thermo-mechanical processing of high-performance Ti alloys has been responsible for improving the reliability and performance of products that use them. Improvements in melting, ingot conversion practice and forging practice all have been contributing factors to this improvement. Modeling of the forging process coupled with hot die forging has led to significant improvements in uniformity of properties. Taken together, these factors have enabled improved reliability of critical components for aerospace applications. This paper describes these improvements and summarizes their benefits. There is room for further improvement, however, the most critical need is reduction of cycle time required to qualify a new forging or a change in forging practice. It is argued that improved models that permit prediction of the microstructure and resulting properties would be of great value. An image of some of the ingredients in improved models will allow this predictive capability will be outlined. (C) 2001 Published by Elsevier Science B.V.