Rene 65 was developed as a nickel-base, gamma prime strengthened, aerospace turbine disk superalloy to provide increased temperature capability compared to direct age (DA) 718 and bridge the performance and cost gap between traditional cast and wrought alloys and powder alloys. A full scale development program was successfully executed to define a robust processing window resulting in successful production introduction of the alloy. Conventional hot die forging, over a wide range of strain rate processes, has been demonstrated as well as successful ring rolling. Optimized heat treatment processing has resulted in approximately 90oC temperature capability increase over DA718 with excellent fatigue and damage tolerance capability. This paper presents results for alloy development, forge processing, heat treatment, microstructure characterization and mechanical property assessment.

The recrystallization behavior of Rene 65 billet was characterized using a combination of sub scale compression samples and full-scale forgings. Two different billet conversion practices were utilized to develop a range o f starting billet microstructures with respect to the percent unrecrystallized grains. These billets provided the sub-scale compression samples and input material for full-scale forgings. Processing parameters studied were strain and strain rate representing a wide range o f forging processes. Strain distributions within the sub-scale compression samples were determined using deformation modeling. Microstructures after compression were mapped as a function of processing parameters. The effect of unrecrystallized grains on low cycle fatigue (LCF) was evaluated.