A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, in
fulfilment of the requirements for the degree of Master of Science in Engineering,
Johannesburg, 1998 / This research examines fatigue in WC-Co, both under compressive and tensile loading conditions.
A new macro-mechanism for compression fatigue crack propagation is put forward, which
contradicts existing data on compression fatigue cracks as being self-limiting. Evidence of this
macro-mechanism is presented in the form of final crack length versus number of cycles data, and
micrographs of the compression fatigue cracks. A finite element study of the stress distribution
in the WC-Co microstructure during compression fatigue loading has been developed. This model
verifies possible methods of compression fatigue crack initiation. Examination of tensile fatigue
and fast: fracture surfaces is used to show that fatigue is a separate mechanism to fast fracture in
WC-Co. Characteristic features of the fatigue fracture surface are presented. A possible fatigue
crack propagation mechanism is also presented. Finally, fatigue crack growth rate data in the form
of the Paris equation is presented for WC-Co grades T6 and G6. / MT2017
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/22772 |
| Date | January 1998 |
| Creators | Erling, Ghita |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | Online resource (130 leaves), application/pdf |
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