In-Vacuum Cyclic Fatigue Behavior of Vanstar-7 at Elevated Temperatures^a

^aThis research was sponsored by the Office of Fusion Energy, U.S. Department of Energy, under contract DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc.

ABSTRACT

Unirradiated Vanstar-7 alloy was tested in fatigue at room temperature, 550°, and 650°C, respectively, in high vacuum below 10⁻⁵ Pa. The test data were analyzed and compared with those of V-15Cr-5Ti and 20% cold-worked type 316 stainless steel tested under the same condition. Results show that the fatigue resistance of Vanstar-7 is in general somewhat lower than that of V-15Cr-5Ti. The low fatigue performance for Vanstar-7 at the elevated temperatures in the high cycle range may be attributable to thermal creep damages because Vanstar-7 is less creep resistant than V-15Cr-5Ti. However, Vanstar-7 exhibits superior fatigue resistance compared with the stainless steel in the low strain range below 0.5% strain.

Notes

^a This research was sponsored by the Office of Fusion Energy, U.S. Department of Energy, under contract DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc.