Brittle materials design, high-temperature gas turbine: Ceramic Turbine Rotor Technology. Interim report No. 13, October 1977--March 1978

Technical Report · Thu Feb 01 00:00:00 EST 1979

OSTI ID:6168001

McLean, A F; Baker, R R

Progress of previous work on reaction bonded and hot pressed silicon nitride materials technology is summarized. Improvements to the hot press bonding process resulted in a significant improvement in the yield of flaw-free hot press bonded rotors. Modulus of rupture and cold spin tests of rotor blade rings revealed the presence of undetected subsurface flaws in both the blades and the rim. Blade bend testing indicated that blade strength degraded during hot press bonding. An investigation of hot press bonding temperatures and time at temperature defined a region of zero microstructural and strength degradation. Using 19 hot press bondings, curves were generated defining the changes in color, porosity, hardness, phase and strength as a function of time and temperature. Improvements in injection molding of rotor blade rings were made utilizing an adaptive process control unit which controlled and monitored the injection velocity and die cavity pressure during the injection and hold portions of the molding cycle. Microfocus x-ray results indicated that high injection flowrates combined with low holding pressures in the die cavity reduced the number of subsurface void-type blade flaws. The detection of planar flaws in both green as-molded and nitrided blade rings revealed that this type flaw was only detectable after nitriding, indicating that it may only occur after burn out and/or nitriding. Approximately 30 experiments were conducted utilizing glass and/or metals as isostatic hot pressing media. Decomposition of the glass was minimized with vycor utilizing boron nitride as a barrier material. A reliability analysis was conducted for individual loading conditions. Recommendations for follow on work are presented.

• Research Organization: Ford Motor Co., Dearborn, MI (USA)
• DOE Contract Number: EY-76-C-02-2630
• OSTI ID: 6168001
• Report Number(s): AMMRC-TR-79-11
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
GAS TURBINES
ROTORS
FABRICATION
PERFORMANCE TESTING
RESEARCH PROGRAMS
SILICON NITRIDES
MATERIALS TESTING
TURBINE BLADES
AUTOMOBILES
BONDING
CERAMICS
DEFECTS
HOT PRESSING
RELIABILITY
SILICON CARBIDES
VERY HIGH TEMPERATURE
CARBIDES
CARBON COMPOUNDS
JOINING
MATERIALS WORKING
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
PRESSING
SILICON COMPOUNDS
TESTING
TURBINES
TURBOMACHINERY
VEHICLES
330103* - Internal Combustion Engines- Turbine