Developing damage tolerance and creep resistance in a high strength nickel alloy for disc applications

The development of an affordable nickel disc alloy that shows the required combination of strength, damage tolerance and creep resistance continues to challenge materials engineers. Rolls-Royce has developed the alloy known as RR1000, which when processed to produce a fine grain microstructure, shows at least a 25 degrees C increase in temperature capability over the current disc alloy, 720Li, and has an equivalent crack growth resistance to coarse grain Waspaloy. This paper discusses the steps that were taken to attain these mechanical properties, and also examines the potential to increase temperature capability by a further 30 degrees C through the development of a coarse microstructure in selected areas of disc forgings.