Accession Number : ADA502557


Title :   Thermo-Mechanical Characterization of Silicon Carbide-Silicon Carbide Composites at Elevated Temperatures Using a Unique Combustion Facility


Descriptive Note : Doctoral Dissertation


Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT


Personal Author(s) : Kim, Ted T


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a502557.pdf


Report Date : 10 Sep 2009


Pagination or Media Count : 344


Abstract : This research investigated four different types of CMCs in a simulated gas turbine engine hot section condition that involved the simultaneous application of a combustion environment and mechanical fatigue loading using a unique burner rig facility developed for this study at AFIT. Three of the materials were woven Melt-Infiltrated (MI) BN/SiC reinforced by Hi-Nicalon Type S (Hi-Nic-S), Sylramic (Syl) and Sylramic with insitu BN coating (Syl-iBN) fibers, respectively. They were made by the slurry cast method. The other CMC was MI Hi-Nic-S/BN/SiC made using the prepreg MI processing. Prepreg MI CMC and Sylramic-iBN fiber reinforced CMC showed better resistance to the fatigue loading in the combustion environment. Thermally induced stress was determined using finite element analysis to be significant in elevating the stress level locally, causing reduction in the overall stress at which sufficient cracking occurs and leads to failure by means of oxidative degradation. Machined edge was susceptible to cracking and subsequently to oxidation that occurred behind the crack tip.


Descriptors :   *COMBUSTION CHAMBERS , *FATIGUE(MECHANICS) , *THERMAL STRESSES , *SILICON CARBIDES , SLURRIES , OXIDATION , SYNCHRONISM , STRESS CORROSION , HEAT , BURNERS , CASTINGS , COMBUSTION , FINITE ELEMENT ANALYSIS , CRACK TIPS , DEGRADATION , HIGH TEMPERATURE


Subject Categories : Inorganic Chemistry
      Mechanics
      Combustion and Ignition


Distribution Statement : APPROVED FOR PUBLIC RELEASE