TE5 DEVELOPKEN!C OF ODS SUPERAILOYS FOR INDUSTRUULGAS TURBINES

Oxide dispersion strengthened CODS) alloys have the significant attribute of being able to retain useful strengths up to a relatively high fraction of their melting points. Moreover at the higher operating temperatures characteristic of advanced gas turbine engines, these alloys display long-term strength beyond the capabilities of conventional superalloys. The increasing use of ODS alloys, particularly in industrial applications, emphasizes the need not only to measure the creep-rupture performance and stability of these alloys but also to predict their behavior in long-term service. Characterization of the long-term properties and structural stability of commercial alloys such as INCONEL" alloy MA 6000 has identified some unique stress rupture behavior characteristics. Two distinct regions of the rupture stress vs. time curves have been identified which together show that higher design stresses for long-term service can be realized than predicted from only short term data. This behavior will be reviewed in relation to the development of a new class of ODS superalloys, typified by INCONEL* alloy MA 760, which combine the long-term strength attributes with the requirements for severe hot corrosion resistance typical of many industrial applications such as gas turbines and similar processes. *INCONEL is a registered trademark of the Into family of companies.