Thermal-Mechanical Fatigue Behavior of Nickel-Base Superalloys.
MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF MATERIALS SCIENCE AND ENGINEERING
Pagination or Media Count:
This report presents the main achievements of a 36-month research program the main objective of which was to gain more insight into the problem of crack growth under thermal mechanical fatigue TMF conditions. The program was arranged into five technical tasks. Under Task I, the goal was to identify the crack propagation conditions in aircraft engines hot section and to assess the validity of conventional fracture mechanics parameters to address TMF crack growth. The second task defined the test facilities, test specimen and the testing conditions needed to establish the effectiveness of data correlation parameters identified in Task I. Under Task III, a computerized testing system to measure the TMF behavior LCF and CG behaviors of various alloy systems was built. A crack propagation test program was defined and conducted under Task IV. The test variables included strain range, strain rate frequency and temperature. Task V correlated and generalized the Task IV data for isothermal and variable temperature conditions so that several crack propagation parameters could be compared and evaluated.
- Metallurgy and Metallography