Effects of Surface Damage on the Fatigue of Copper Single Crystals.

White, Joan D. M. (1984) Effects of Surface Damage on the Fatigue of Copper Single Crystals. Doctoral thesis, University of Surrey (United Kingdom)..

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Abstract

Damage in the form of Vickers indentations was introduced into the carefully prepared surfaces of copper single crystals. The specimens were cycled in reversed bending at a low strain amplitude (Et ~ 8 x 10[-4]). Preliminary experiments showed that persistent slip bands readily nucleated in the locality of the indentations but did not form in the regions between them. Subsequent experiments were designed to isolate the features of the indentation primarily responsible for the enhanced formation of PSBs. Potential causes of local stress enhancement were considered to include stress concentration due to a surface pit, stress enhancement near a hardened zone centred on the indentation and residual stresses. Simple models were developed and the stress distributions associated with each of these effects were calculated. The results both of experiments and the calculations of the stress distribution showed that the enhanced PSB formation near indentations was an effect of the plastic deformation produced by indentation rather than a result of stress concentration near a surface pit. However, the results of fatigue tests in which specimens were annealed after indentation showed that such stress concentrators were potentially damaging. These experiments also showed that the dislocation structures remaining in the locality of indentations after high temperature annealing treatments contributed to the enhanced nucleation of PSBs.

Item Type:	Thesis (Doctoral)
Divisions :	Theses
Authors :	Name Email ORCID White, Joan D. M.
Date :	1984
Contributors :	Contribution Name Email ORCID http://www.loc.gov/loc.terms/relators/THS
Additional Information :	Thesis (Ph.D.)--University of Surrey (United Kingdom), 1984.
Depositing User :	EPrints Services
Date Deposited :	22 Jun 2018 15:17
Last Modified :	06 Nov 2018 16:54
URI:	http://epubs.surrey.ac.uk/id/eprint/848559

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