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Plasticity‐Controlled Friction and Wear in Nanocrystalline SiC
Author(s) -
Mishra Maneesh,
Tangpatjaroen Chaiyapat,
Szlufarska Izabela
Publication year - 2014
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.12810
Subject(s) - materials science , nucleation , nanocrystalline material , silicon carbide , grain boundary , composite material , deformation mechanism , nanoscopic scale , scratch , grain boundary sliding , deformation (meteorology) , ceramic , grain size , carbide , plasticity , microstructure , nanotechnology , chemistry , organic chemistry
Wear resistance of ceramics can be improved by suppressing fracture, which can be accomplished either by decreasing the grain size or by reducing the size of the deformation zone. We have combined these two strategies with the goal of understanding the atomistic mechanisms underlying the plasticity‐controlled friction and wear in nanocrystalline (nc) silicon carbide ( SiC ). We have performed molecular dynamics simulations of nanoscale wear on nc‐ SiC with 5 nm grain diameter with a nanoscale cutting tool. We find that grain‐boundary ( GB ) sliding is the primary deformation mechanism during wear and that it is accommodated by heterogeneous nucleation of partial dislocations, formation of voids at the triple junctions, and grain pull‐out. We estimate the stresses required for heterogeneous nucleation of partial dislocations at triple junctions and shear strength of GB s. Pile up in nc‐ SiC consists of grains that were pulled out during deformation. We compare the wear response of nc‐ SiC to single‐crystal (sc) SiC and show that scratch hardness of nc‐ SiC is lower than that of sc‐ SiC . Our results demonstrate that the higher scratch hardness in sc‐ SiC originates from nucleation and motion of dislocations, whereas nc‐ SiC is more pliable due to additional mechanism of deformation via GB sliding.