Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 4 of 4
Full-Text Articles in Engineering
Creep Of Nextel 720/A Ceramic Matrix Composite With Laser Drilled Effusion Holes At 1200°C In Air And In Steam, Savannah N. Minor
Creep Of Nextel 720/A Ceramic Matrix Composite With Laser Drilled Effusion Holes At 1200°C In Air And In Steam, Savannah N. Minor
Theses and Dissertations
Creep behavior of an oxide-oxide ceramic matrix composite (CMC) containing an array of effusion holes was investigated at 1200⁰C in air and in steam. The composite (N720/A) consisted of a porous alumina matrix reinforced with alumina-mullite NextelTM 720 fibers. Test specimens had an array of 17 effusion holes with 0.5-mm diameter. The effusion holes were drilled through the specimen thickness normal to the specimen surface using a CO2 laser. Effect of the effusion holes on tensile properties was evaluated tension tests to failure at 1200°C in air. Creep of specimens with effusion holes at 1200°C was studied for creep stresses …
Creep Of Hafnium Diboride -20 Vol% Silicon Carbide At 1500°C In Air, Glen E. Pry
Creep Of Hafnium Diboride -20 Vol% Silicon Carbide At 1500°C In Air, Glen E. Pry
Theses and Dissertations
Refractory metal borides, commonly referred to as Ultra High Temperature Ceramics (UHTCs), exhibit a number of unique properties, such as extremely high melting temperature and hardness, chemical stability, high electrical and thermal conductivity and corrosion resistance. It has been demonstrated that the addition of SiC improves the oxidation resistance of ZrB2- and HfB2-based UHTCs above 1200°C by modifying the composition of the oxide scale. Addition of SiC retards the oxidation rate of ZrB2 and HfB2 by forming a protective layer of borosilicate glass. Creep deformation is one of the critical criterion for structural application of ceramics at elevated temperatures. Compression …
Tensile Properties And Fatigue Behavior Of Geopolymer Matrix Composites With Carbon Fiber Reinforcement At Elevated Temperature, Steffan M.L. Wilcox
Tensile Properties And Fatigue Behavior Of Geopolymer Matrix Composites With Carbon Fiber Reinforcement At Elevated Temperature, Steffan M.L. Wilcox
Theses and Dissertations
The tensile stress-strain and tension-tension fatigue of geopolymer matrix composites reinforced with 0/90 carbon fibers was investigated at 23 and 300°C in laboratory air. Geopolymers are inorganic polymeric materials composed of alumina, silica, and alkali metal oxides. Because geopolymers are synthesized as a fluid mixture or particles and liquid, they can be cast into a desired shape, and cured at only slightly elevated temperatures. The relative ease of synthesis and low processing temperatures make geopolymers an attractive choice as a matrix material for composite materials. Geopolymers also offer resistance to heat and oxidizing environments. Currently, geopolymer matrix composites are being …
Influence Of Coolant Flow Rate Parameters In Scaling Gas Turbine Cooling Effectiveness On A Flat Plate, Jacob P. Fischer
Influence Of Coolant Flow Rate Parameters In Scaling Gas Turbine Cooling Effectiveness On A Flat Plate, Jacob P. Fischer
Theses and Dissertations
Effective film cooling relies on the performance of the selected cooling hole shape and placement of the holes on the surface of the blade. To test each holes effectiveness, large scale, low-temperature testing has been used to reduce cost and complexity. The resulting quantity from this testing is called the adiabatic effectiveness (n). The adiabatic effectiveness can then scaled up to engine operating conditions to predict how the selected film cooling hole will perform. This process is complicated by the nonlinear variation of gas properties between coolant and freestream conditions as well as between the experimental and engine conditions. In …