SHORT FATIGUE-CRACK GROWTH-BEHAVIOR IN WASPALOY AT ROOM AND ELEVATED-TEMPERATURES

Short fatigue crack growth tests have been carried out at room and ele vated temperatures using the nickel-based superalloy known as Waspaloy . A fully automated computer controlled system has been developed and employed for controlling the testing and monitoring of the growth of f reely initiated surface short cracks on smooth specimens. Surface crac ks as small as 10 mu m in length have been detected and recorded at te mperatures up to 700 degrees C. Anomalous short crack propagation beha viour was observed when comparisons were made with the corresponding l ong crack behaviour. Some aspects of mechanical microstructural and en vironmental effects on the short fatigue crack growth behaviour of the material are discussed.