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Optimum Microstructure of Transformation‐Toughened Ceramics for Enhanced Wear Performance
Author(s) -
Thomsen Niels B.,
Karihaloo Bhushan L.
Publication year - 1995
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.1151-2916.1995.tb08353.x
Subject(s) - materials science , volume fraction , microstructure , ceramic , composite material , cubic zirconia , enhanced data rates for gsm evolution , toughness , layer (electronics) , surface layer , phase (matter) , volume (thermodynamics) , surface (topology) , geometry , mathematics , telecommunications , chemistry , physics , organic chemistry , quantum mechanics , computer science
The poor rolling/sliding wear performance of transformation‐toughened ceramics such as partially stabilized zirconia (PSZ) is believed to be a result of the phase transformation of precipitates located immediately beneath the contacting surface. These very precipitates, on the other hand, enhance the toughness of the ceramic by preventing the growth of surface cracks. In order to find a compromise solution, an optimization problem is formulated for an idealized model consisting of an edge crack normal to the contacting surface and a periodic distribution of transformable grains in the layer immediately beneath this surface. The objective is to maximize the crack tip shielding by varying the volume fraction and size of the layer without exceeding a prescribed allowable surface uplift. It is shown that maximum volume fraction is attained at a certain depth below the surface but that its magnitude is considerably smaller than that pertaining in peak‐aged PSZ.