The influence of loading frequency on the high-temperature fatigue behavior of a Nicalon-fabric-reinforced polymer-derived ceramic-matrix composite

Journal Article · Tue May 12 04:00:00 EDT 1998 · Scripta Materialia

DOI:https://doi.org/10.1016/S1359-6462(98)00105-5· OSTI ID:619523

Vanswijgenhoven, E ^[1]; Holmes, J ^[1]; Wevers, M ^[2]; Szweda, A ^[3]

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1. Univ. of Michigan, Ann Arbor, MI (United States). Ceramic Composites Research Lab.
2. Katholieke Univ. Leuven (Belgium). Dept. Metaalkunde en Toegepaste Materiaalkunde
3. Dow Corning Corp., Midland, MI (United States). Advanced Ceramics Program

Fiber-reinforced ceramic-matrix composites are under development for high-temperature structural applications. These applications involve fatigue loading under a wide range of frequencies. To date, high-temperature fatigue experiments have typically been performed at loading frequencies of 10 Hz or lower. At higher frequencies, a strong effect of loading frequency on fatigue life has been demonstrated for certain CMC`s tested at room temperature. The fatigue life of CMC`s with weak fiber-matrix interfaces typically decreases as the loading frequency increases. This decrease is attributed to frictional heating and frequency dependent interface and fiber damage. More recently, it has been shown that the room temperature fatigue life of a Nicalon-fabric-reinforced composite with a strong interface (SYLRAMIC{trademark}) appears to be independent of loading frequency. The high-temperature low-frequency fatigue behavior of the SYLRAMIC composite has also been investigated. For a fatigue peak stress {sigma}{sub peak} above a proportional limit stress of 70 MPa, the number of cycles to failure N{sub f} decreased with an increase in {sigma}{sub peak}. The material endured more than 10{sup 6} cycles for {sigma}{sub peak} below 70 MPa. In this paper, the influence of loading frequency on the high-temperature fatigue behavior of the SYLRAMIC composite is reported. It will be shown that the fatigue limit is unaffected by the loading frequency, that the number of fatigue cycles to failure N{sub f} increases with an increase in frequency, and that the time to failure t{sub f} decreases with an increase in frequency.

• OSTI ID: 619523
• Journal Information: Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 12 Vol. 38; ISSN 1359-6462; ISSN SCMAF7
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
FREQUENCY DEPENDENCE
HEAT RESISTANT MATERIALS
POLYMERS
REINFORCED MATERIALS
SILICON CARBIDES
THERMAL FATIGUE