Fatigue Behavior of an Advanced SiC/SiC Composite at 1300 deg C in Air and Steam
Abstract
The fatigue behavior of an advanced silicon carbide/silicon carbide (SiC/SiC) ceramic matrix composite (CMC) was investigated at 1300 deg C in laboratory air and in steam environments. The composite was manufactured using chemical vapor infiltration (CVI). The composite consisted of an oxidation-inhibited matrix, which was comprised of alternating layers of silicon carbide and boron carbide and was reinforced with laminated Hi-Nicalon fibers woven in a plain weave. Fiber preforms had pyrolytic carbon fiber coating with boron carbon overlay applied. Two specimen geometries were evaluated, a dog bone and an hour glass geometry. Tensile stress strain behavior and tensile properties were evaluated at 1300 deg C. Tension-tension fatigue tests were conducted in both laboratory air and in steam at 1300 deg C at 1.0 Hz with a minimum to maximum stress ratio of R = 0.05. Fatigue behavior was evaluated for a maximum stress of 70-160 MPa in air and in steam environments. Fatigue run-out was defined as 2 x 10(exp 5) cycles. Strain accumulation with cycles and modulus evolution with cycles were analyzed for each fatigue test. The CMC fatigue performance was affected little by the presence of steam. The fatigue limit was between 80 and 100 MPa. Retained tensile properties were characterized for all specimens that achieved fatigue run-out. Failure surfaces were examined to study composite microstructure as well as damage and failure mechanisms.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2016
- Accession Number
- AD1054171
Entities
People
- Michael D Lee
Organizations
- Air Force Institute of Technology