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Unformatted text preview: ies. Grain Boundaries as Obstacles to Slip Single Crystal versus Polycrystal Strength GRAIN BOUNDARIES
Grain boundaries strengthen materials by acting
as barriers to dislocation movement (less at high
Small grains are desirable for improved strength
at room temperature, as smaller grains means
more frequent grain boundaries. TEM of Dislocation Pile up at Grain Boundary PLASTIC DEFORMATION
Grain shape: With increased deformation, grains
elongate in the direction of the
Dislocations: Form cells that become elongated
in the direction of deformation. 30% Cold-Rolled Copper 50% Cold Rolled Copper TEM Substructure of 30% Cold Rolled Copper TEM Substructure of 50% Cold Rolled Copper COLD WORKING (STRAIN HARDENING)
Strengthening by increasing dislocation density
during deformation. As strain increases it
becomes more difficult for the...
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This document was uploaded on 02/27/2014 for the course NANO 108 at UCSD.
- Fall '13