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Local strain accumulation in fatigue crack propagation process of Ti‐6Al‐4V alloy
Author(s) -
Ye S.,
Gong J. G.,
Tu S. T.,
Zhang X. C.,
Zhang C. C.
Publication year - 2017
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.12559
Subject(s) - materials science , microstructure , paris' law , crack closure , alloy , digital image correlation , titanium alloy , metallurgy , stress concentration , von mises yield criterion , fracture mechanics , fatigue testing , strain (injury) , composite material , structural engineering , finite element method , medicine , engineering
Abstract Fatigue crack growth behaviours of the titanium alloy Ti‐6Al‐4V, with two different microstructures, at different maximum stresses were identified by digital image correlation technique. Full‐field strains were monitored around fatigue cracks after consecutive cycles in fatigue crack growth experiments. Results indicated that the Ti‐6Al‐4V alloy with a bi‐modal microstructure had a better fatigue resistance than that with a primary‐α microstructure. Typical behaviours of small cracks and the evolution of multi‐scale fatigue cracks were clarified. The strain accumulations around the micro‐notch and fatigue crack increased with increasing number of load cycles. On the basis of von Mises strain mapping, it was found that crack growth rate could be characterized by crack‐tip plastic zone size .