Reduction of Strategic Elements in Turbine Disk Alloys.
Abstract
A study was conducted to characterize the effect of the substitution of nickel for cobalt in a modified IN100 alloy. The stacking fault energy of the austenitic matrix and the mechanical properties of both the matrix phase alloy and the superalloy were determined as a function of cobalt content. Among the mechanical properties evaluated - yield strength, creep, and low cycle fatigue, the effect of cobalt is most pronounced in creep. Substitution of nickel for all the cobalt (18%) in the alloy leads to a drastic reduction of creep rupture life and some decrease in ductility. However, intermediate levels of substitution (10%) have no adverse effect on creep properties. These results were confirmed in the AF115 alloy. Detailed studies of the microstructural and deformation characteristics of the alloys as a function of cobalt content revealed several important factors. Stacking fault energy, although low in alloys, did vary sufficiently to lower creep resistance. In addition, the changes in precipitation processes for both the gamma prime and carbide phases also tended to degrade the creep capability. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1981
- Accession Number
- ADA102074
Entities
People
- C. C. Law
- J. S. Lin
- M. J. Blackburn
Organizations
- Pratt & Whitney