Some Aspects of Fatigue Crack Closure in Titanium Alloys.
Abstract
Fatigue crack growth at intermediate rates and R 0.1 has been measured in compact tension specimens of the alloys Ti-6Al-4V and Ti-6Al-5Zr-0.5Mo-0.25Si. Crack length was determined from the output of a crack mouth displacement gauge and by using a d.c. potential drop technique. The incidence of crack closure was examined during fatigue by using both of the above methods; COD was found to be more reliable for closure measurement than potential drop. In contrast to the fine microstructured Ti-6Al-4V, the coarse Ti-6Al-5Zr-0.5Mo-0.25Si showed substantial load transfer across the crack faces during fatigue and this was attributed to a 'non-closure' mechanism. Low crack growth rates in the latter alloy were rationalized in terms of an effective delta K. Marked reductions in growth rate produced by variable amplitude loading ot Ti-6Al-4V could not be explained by crack closure. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 31, 1979
- Accession Number
- ADA076948
Entities
People
- C. J. Beevers
Organizations
- University of Birmingham