High Temperature Fatigue Behavior of Tungsten Copper Composites PDF Download

Author: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
ISBN: 9781792754432
Category : Science
Languages : en
Pages : 36

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Book Description
The high temperature fatigue behavior of a 9 vol percent, tungsten fiber reinforced copper matrix composite was investigated. Load-controlled isothermal fatigue experiments at 260 and 560 C and thermomechanical fatigue (TMF) experiments, both in phase and out of phase between 260 and 560 C, were performed. The stress-strain response displayed considerable inelasticity under all conditions. Also, strain ratcheting was observed during all the fatigue experiments. For the isothermal fatigue and in-phase TMF tests, the ratcheting was always in a tensile direction, continuing until failure. The ratcheting during the out-of-phase TMF test shifted from a tensile direction to a compressive direction. This behavior was thought to be associated with the observed bulging and the extensive cracking of the out-of-phase specimen. For all cases, the fatigue lives were found to be controlled by damage to the copper matrix. Grain boundary cavitation was the dominant damage mechanism of the matrix. On a stress basis, TMF loading reduced lives substantially, relative to isothermal cycling. In-phase cycling resulted in the shortest lives, and isothermal fatigue at 260 C, the longest. Verrilli, Michael J. and Kim, Yong-Suk and Gabb, Timothy P. Glenn Research Center NASA-TM-102404, E-5156, NAS 1.15:102404 RTOP 510-01-0A...