Fracture Stress as Related to Flaw and Fracture Mirror Sizes in Two Polycrystalline Ceramics.
Abstract
Fractographically observed critical-flaw boundaries in strength-tested specimens of two polycrystalline ceramics were used in calculating critical stress-intensity factors. Each ceramic was found to exhibit a characteristic stress-intensity factor (K sub IC) having little or no dependence on critical-flaw characteristics. Also, the research indicated that microstructural inhomogenities (e.g., large grains or pores) which initiate fracturing can be significantly smaller than associated critical flaws. The fractographic interpretations of critical-flaw boundaries were supported by independent determinations of K sub IC using artificially precracked specimens and by analyses both of fracture-mirror sizes and of water-enhanced sub-critical crack growth data. The fracture-mirror analysis further indicated that the parameter, A K sub IC, where A is the fracture-mirror constant, is a dimensionless, material-independent constant that can be evaluated solely from fractographic observations. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1976
- Accession Number
- ADA027698
Entities
People
- Girraj K. Bansal
- Winston H. Duckworth
Organizations
- Battelle Memorial Institute