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Subsurface deformation of machined Al 2 O 3 and Al 2 O 3 /5vol%SiC nanocomposite
Author(s) -
Wu H.,
Inkson B. J.,
Roberts S. G.
Publication year - 2001
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1046/j.1365-2818.2001.00768.x
Subject(s) - materials science , crystal twinning , deformation (meteorology) , dislocation , nanocomposite , grain boundary , composite material , transmission electron microscopy , grain size , intergranular corrosion , grinding , crystallography , condensed matter physics , microstructure , nanotechnology , chemistry , physics
Under machine grinding, material removal in monolithic Al 2 O 3 is by intergranular fracture and grain pull‐out. In comparison, under the same grinding conditions, an Al 2 O 3 /5%SiC nanocomposite undergoes significant surface grooving and intragranular fracture. The subsurface deformation mechanisms were investigated by cross‐sectional transmission electron microscopy. For Al 2 O 3 , the residual deformation zone was localized very close to the surface in the first layer of grains, with dislocations occurring only within 1.5 µm of the top surface and a high density of basal twins penetrating to a depth of one single grain. Cracks were present along grain boundaries or basal twin interfaces. For Al 2 O 3 /SiC nanocomposites, the main residual plastic deformation is observed to be dislocations activated to a depth of about 10 µm (approx. 3–4 grains), with twinning rarely observed. Possible mechanisms by which the SiC particles influence the subsurface deformation and material removal modes are discussed.