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Very high‐cycle fatigue behaviour of T i‐6 A l‐4 V alloy under corrosive environment
Author(s) -
Zhao P.C.,
Li S.X.,
Jia Y.F.,
Zhang C.C.,
Zhang X.C.,
Tu S.T.
Publication year - 2018
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.12735
Subject(s) - materials science , fatigue limit , alloy , fatigue testing , cracking , microstructure , metallurgy , titanium alloy , lüders band , slip (aerodynamics) , fatigue cracking , composite material , physics , thermodynamics
Rotary‐bending fatigue tests of Ti‐6Al‐4V alloy at very high‐cycle regime were performed in air and 3.5% NaCl solution, respectively. The S‐N curves exhibited the characteristic of horizontal asymptote (traditional fatigue limit) in laboratory air, while a lower fatigue limit was shown in 3.5% NaCl solution after around 3 × 10 8 cycles. The decrease of fatigue life was due to the generation of small surface defects in comparison with that in air. These defects were ascribed to the hydrogen‐induced cracking and fatigue loading. The number of fatigue crack initiation sites decreases with increasing cycles. Only one crack origin site, dominated by slip mechanism, exists in each specimen at very high‐cycle regime. The existing experimental S‐N data of Ti‐6Al‐4V alloy from very high‐cycle fatigue tests were also reviewed. It was shown that the fatigue life ( R = −1) of Ti‐6Al‐4V alloy was predominantly influenced by the microstructure and not strongly sensitive to the loading mode and frequency (in the range from 52.5 Hz to 20 kHz) under air condition at room temperature.