Localized Impact Damage in Ceramics.
Abstract
Two topics are covered in this report: (1) Localized impact damage in hot pressed Si3N4 and SiC and, (2) Effect of leached surface layers on impact damage and remaining strength of Si3N4. The impact force necessary to form Hertz cracks in H.P. Si3N4 was about four times that for SiC. The Hertz cracks were characterized and the dimensions were compared with calculated values. The crack depths and the strength degradation were less than expected based on the available theory. H.P. Si3N4 was leached with HF and subjected to impact at low velocities by a tungsten carbide sphere. The remaining strength of the leached material after impact was substantially greater than that of impact damaged specimens that were not leached. The leached layers prevented formation of Hertz cracks in the underlying material. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1976
- Accession Number
- ADA021496
Entities
People
- Craig S. Miller
- Henry P. Kirchner
- Robert M. Gruver