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Effects of Crystal Orientation and Temperature on the Strength of Sapphire
Author(s) -
Schmid Frederick,
Harris Daniel C.
Publication year - 1998
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.1151-2916.1998.tb02423.x
Subject(s) - compressive strength , materials science , ultimate tensile strength , crystal twinning , composite material , compression (physics) , sapphire , crystal (programming language) , microstructure , optics , laser , physics , computer science , programming language
The flexure and compressive strengths of sapphire are dependent on crystal orientation and temperature. Most notably, the c ‐axis compressive strength decreases below the tensile strength at temperatures >400°C and falls to 2% of the room‐temperature compressive strength at 800°C. Loss of compressive strength complicates the interpretation of flexure tests. Four‐point flexure specimens with no component of c ‐axis compression increase in strength at temperatures >500°C; however, specimens that have c ‐axis compression decrease in strength. It has been observed that c ‐axis compression causes twinning on rhombohedral crystal planes. Intersection of twins on different rhombohedral planes causes fracture that leads to mechanical failure.