In-vacuum cyclic fatigue behavior of Vanstar-7 at elevated temperatures
Refractory metal alloys have been proposed for fusion reactor and space power applications because of their high temperature strength, low thermal stress properties, good compatibility with liquid metal coolants and radiation resistance. However, little is known about the cyclic fatigue properties which are important to some fusion reactor first wall systems that operate in thermal cycles. This paper presents limited results of in-vacuum cyclic fatigue tests on Vanstar-7 (9Cr-3Fe-Zr) at room temperature, 550 and 650/sup 0/C. Miniature hourglass-shaped specimens were used with a gage diameter of 3.18 mm. The material was annealed 1 h in vacuum at 1400/sup 0/C before machining, to produce an average grain size of ASTM No. 7. The specimens were stress relieved for 0.5 h at 1400/sup 0/C after machining. Tests were performed on a servocontrolled hydraulic testing system equipped with a vacuum chamber capable of pressures below 10/sup -5/ Pa. Specimens were heated by an induction heater, maintaining temperatures within +-2/sup 0/C of the nominal temperature during the test. A diametral extensometer was used, but axial strain calculated via a strain computer was used for machine control. A fully reversed triangular wave function beginning with compression was employed at a strain rate of 4 x 10/sup -3/ s/sup -1/ for all low-cycles tests. High cycle testing was conducted initially in strain control but switched to load control after stable essentially elastic cycling was established.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6042885
- Report Number(s):
- CONF-860610-21; ON: DE86007322
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360103* -- Metals & Alloys-- Mechanical Properties
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700209 -- Fusion Power Plant Technology-- Component Development & Materials Testing
ALLOYS
CHROMIUM ALLOYS
ELASTICITY
FATIGUE
HIGH TEMPERATURE
IRON ALLOYS
MECHANICAL PROPERTIES
NESDPS Office of Nuclear Energy Space and Defense Power Systems
STRAINS
TENSILE PROPERTIES
THERMAL CYCLING
VANADIUM ALLOYS
VANADIUM BASE ALLOYS
VANSTAR 7
ZIRCONIUM ALLOYS