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Improved silicon nitride for advanced heat enginesThe technology base required to fabricate silicon nitride components with the strength, reliability, and reproducibility necessary for actual heat engine applications is presented. Task 2 was set up to develop test bars with high Weibull slope and greater high temperature strength, and to conduct an initial net shape component fabrication evaluation. Screening experiments were performed in Task 7 on advanced materials and processing for input to Task 2. The technical efforts performed in the second year of a 5-yr program are covered. The first iteration of Task 2 was completed as planned. Two half-replicated, fractional factorial (2 sup 5), statistically designed matrix experiments were conducted. These experiments have identified Denka 9FW Si3N4 as an alternate raw material to GTE SN502 Si3N4 for subsequent process evaluation. A detailed statistical analysis was conducted to correlate processing conditions with as-processed test bar properties. One processing condition produced a material with a 97 ksi average room temperature MOR (100 percent of goal) with 13.2 Weibull slope (83 percent of goal); another condition produced 86 ksi (6 percent over baseline) room temperature strength with a Weibull slope of 20 (125 percent of goal).
Document ID
19890010050
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Yeh, Hun C.
(AiResearch Casting Co. Torrance, CA., United States)
Fang, Ho T.
(Garrett Turbine Engine Co. Phoenix, AZ., United States)
Date Acquired
September 5, 2013
Publication Date
February 1, 1987
Subject Category
Nonmetallic Materials
Report/Patent Number
NASA-CR-179525
NAS 1.26:179525
AIRESEARCH-86-60365
Accession Number
89N19421
Funding Number(s)
CONTRACT_GRANT: NAS3-24385
PROJECT: RTOP 533-05-01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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