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Blunt scratch strength of polycrystalline alumina
Author(s) -
Cook Robert F.
Publication year - 2018
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.15190
Subject(s) - materials science , indentation , scratch , brittleness , composite material , crystallite , stress intensity factor , residual strength , deformation (meteorology) , compressive strength , fracture (geology) , residual stress , intensity (physics) , fracture mechanics , optics , metallurgy , physics
A model for the fracture strength of brittle materials controlled by blunt (spherical) scratches is developed and compared with measurements on a polycrystalline alumina. The model is based on a residual stress‐intensity factor for median cracks at scratches that include a localized plastic deformation zone formed by dragged spherical contacts. The stress‐intensity factor depends nonlinearly on the normal contact load P , resulting in a predicted strength variation of P −3/4 . The strength result validates previous claims and extends the overall indentation‐strength framework. However, the result has only limited effectiveness in describing experimental measurements, pertaining only to ideal blunt scratches formed over a limited load domain.