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Influence of artificial and casting defects on fatigue strength of moulded components in Ti‐6Al‐4V alloy
Author(s) -
Léopold G.,
Nadot Y.,
Billaudeau T.,
Mendez J.
Publication year - 2015
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/ffe.12326
Subject(s) - materials science , fatigue limit , machining , alloy , casting , fatigue testing , titanium alloy , metallurgy , reduction (mathematics) , composite material , structural engineering , engineering , mathematics , geometry
The influence of defects on the fatigue strength of a cast Ti‐6Al‐4V alloy has been investigated. An experimental programme has been defined with different castings. On a first stage, a flat fatigue specimen has been developed to be representative of the real aircraft component. Then, reference fatigue properties have been determined and reduction of the fatigue strength has been quantified for artificial and natural defects. It is shown that an artificial defect with a chemically milled surface is representative of an in‐service component surface machining: surface pinholes have similar influence on the fatigue behaviour. Furthermore, the experimental results have shown that the geometrical morphology is not the major parameter that governs the fatigue life reduction: the defect type has a major influence. It is also shown that the initiation stage is not negligible in the total fatigue life about 10 5 cycles. Kitagawa diagrams were built to determine critical defect sizes.