| About this Abstract |
| Meeting |
MS&T21: Materials Science & Technology
|
| Symposium
|
Ceramic Matrix Composites
|
| Presentation Title |
Static Fatigue of Hi-Nicalon-S Fiber Tows at Elevated Temperature in Air and in Steam |
| Author(s) |
Scott Robertson, Marina Ruggles-Wrenn, Randall Hay, Theodore Shillig , Ronald Mitchell , Brian Kroeger , Logan Gumucio |
| On-Site Speaker (Planned) |
Marina Ruggles-Wrenn |
| Abstract Scope |
A facility for testing SiC fiber tows in static fatigue at elevated temperatures in air, in steam and in steam saturated with silicic acid was developed. Static fatigue of Hi-Nicalon™-S fibers was investigated at 800-1100°C at stresses of 115-1250 MPa in air, in steam, and in steam saturated with silicic acid. Fibers tested in silicic acid-saturated steam and in air had silica scales throughout the test sections, but those tested in unsaturated steam did not develop scales near the steam injection point. The presence of steam reduced fiber lifetimes under static fatigue. Fiber lifetimes were much shorter in unsaturated steam than in Si(OH)4(g)-saturated steam. Failure strains did not exceed 0.3%. Steady–state strain rates and static fatigue lifetimes are modelled empirically by the Monkman–Grant relationship. The MG relationship was demonstrated to successfully predict creep lifetimes in air, steam and steam saturated with silicic acid. Failure mechanisms are discussed. |