8-Mechanical Behavior

8-Mechanical Behavior

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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 temperatures). 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 deformation. 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.

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