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Flexure Strength, Fracture Toughness, and Slow Crack Growth of YSZ/Alumina Composites at High Temperatures
Author(s) -
Choi Sung R.,
Bansal Narottam P.
Publication year - 2005
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.1551-2916.2005.00252.x
Subject(s) - composite material , materials science , fracture toughness , composite number , yttria stabilized zirconia , flexural strength , cubic zirconia , particulates , toughness , ceramic , chemistry , organic chemistry
Flexure strength and fracture toughness of zirconia–alumina composites, fabricated by hot pressing 10 mol% yttria‐stabilized zirconia (10‐YSZ) reinforced with 0–30 mol% alumina particulates or platelets, were determined as a function of alumina content at 1000°C in air. Both strength and fracture toughness of the two composite systems increased with increasing alumina content. For a given alumina content, flexure strength of the particulate composites was greater than that of the platelet composites at higher alumina contents (≥20 mol%); whereas, fracture toughness of the platelet composites was greater than that of the particulate counterparts, regardless of the alumina content. The susceptibility to slow crack growth (SCG), determined at 1000°C via constant stress‐rate testing, was greatest for 30 mol% particulate composite with SCG parameter n =5–8 and was least for 30 mol% platelet composite with n =33. Elastic modulus of both composite systems decreased below 400°C and then remained almost unchanged up to 1000°C, forming a unique transition around 400°C, irrespective of alumina content.