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Foreign Object Damage of Two Gas-Turbine Grade Silicon Nitrides in a Thin Disk ConfigurationForeign object damage (FOD) behavior of two commercial gas-turbine grade silicon nitrides, AS800 and SN282, was determined at ambient temperature through post-impact strength testing for thin disks impacted by steel-ball projectiles with a diameter of 1.59 mm in a velocity range from 115 to 440 m/s. AS800 silicon nitride exhibited a greater FOD resistance than SN282, primarily due to its greater value of fracture toughness (K(sub IC)). The critical impact velocity in which the corresponding post-impact strength yielded the lowest value was V(sub c) approx. 440 and 300 m/s for AS800 and SN282, respectively. A unique lower-strength regime was typified for both silicon nitrides depending on impact velocity, attributed to significant radial cracking. The damages generated by projectile impact were typically in the forms of ring, radial, and cone cracks with their severity and combination being dependent on impact velocity. Unlike thick (3 mm) flexure bar specimens used in the previous studies, thin (2 mm) disk target specimens exhibited a unique backside radial cracking occurring on the reverse side just beneath the impact sites at and above impact velocity of 160 and 220 m/s for SN282 and AS800, respectively.
Document ID
20030111835
Acquisition Source
Glenn Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Choi, Sung R.
(NASA Glenn Research Center Cleveland, OH, United States)
Pereira, J. Michael
(NASA Glenn Research Center Cleveland, OH, United States)
Janosik, Lesley A.
(NASA Glenn Research Center Cleveland, OH, United States)
Bhatt, Ramakrishna T.
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
September 7, 2013
Publication Date
January 1, 2003
Subject Category
Nonmetallic Materials
Report/Patent Number
GT2003-38544
Meeting Information
Meeting: ASME Turbo Expo 2003 Power of Land, Sea and Air
Location: Atlanta, GA
Country: United States
Start Date: June 16, 2003
End Date: June 19, 2003
Sponsors: American Society of Mechanical Engineers
Funding Number(s)
OTHER: 708-31-09
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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