The Effect of Predeformation on the Creep Behavior and Rupture Life of MA 754.
Abstract
Tests were conducted on a nickel-base superalloy after predeforming the material by applying a high strain (2 x 10 -5 sec -1) to the specimens before creep testing. The effect of the predeformation of the creep behavior and stress rupture life was evaluated. The material tested was a nickel-base, oxide dispersion strengthened solid solution alloy developed by the International Nickel Company called MA 754. The material is formed by mechanical alloying and powder metallurgy techniques. After predeforming the specimens by applying 276 MPa stress until the desired amount of prestrain was attained, the specimens were crept at 224 MPa until failure. Both predeformation and creep testing were conducted at 760 degrees C. The minimum creep rate decreased as the amount of prestrain applied increased and was a factor of two lower than the standard at 1.2% prestrain. Also, the prestrained specimens reached their minimum creep rates in a shorter period of time than the standard specimens. The rupture life increased with increasing amounts of prestrain up to 0.6% prestrain and then decreased with further prestrain, but was still slightly greater than the life of the standard at 1.2% prestrain. Transmission electron microscopy revealed dislocations being emitted from particle-matrix interfaces and an apparent increase in dislocation density with increasing amounts of prestrain. The observations suggest that a dispersion hardening effect may be occurring. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1979
- Accession Number
- ADA091458
Entities
People
- Robert Thomas Marlin
Organizations
- Air Force Institute of Technology