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Correlation of Machining‐Grain‐Size Effects on Tensile Strength with Tensile Strength–Grain‐Size Behavior
Author(s) -
Rice Roy W.
Publication year - 1993
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/j.1151-2916.1993.tb05339.x
Subject(s) - ultimate tensile strength , perpendicular , materials science , machining , grinding , grain size , composite material , elongation , ceramic , metallurgy , geometry , mathematics
Existing data on the effect of machining direction on the room‐temperature flexure strength (σ) of various ceramic materials are reviewed from the standpoint of their grain‐size ( G ) dependence and the correlation of this dependence with σ‐ G ‐1/2 behavior. The correlation shows that the reduction in strength from grinding specimens perpendicular versus parallel to their tensile axes is greatest at fine G , about zero at intermediate G , and then progressively increases again for larger G and for single‐crystal specimens ( G =∞). The lower σ due to machining perpendicular to versus parallel to the tensile axis is due primarily to crack shape, not depth, i.e., elongated and approximately half‐penny cracks. Thus, the reduction in σ difference implies a reduction in flaw elongation at intermediate G . This is shown to correspond with the σ‐ G ‐1/2 behavior with larger G and finer G branches meeting when the flaw size is about equal to G . This result is supported by fractographic observations.