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MICROSTRUCTURAL EFFECTS ON SMALL FATIGUE CRACK INITIATION AND GROWTH IN Ti6A14V ALLOYS
Author(s) -
Demulsant X.,
Mendez J.
Publication year - 1995
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/j.1460-2695.1995.tb00870.x
Subject(s) - coalescence (physics) , materials science , microstructure , nucleation , titanium alloy , crack closure , metallurgy , composite material , grain boundary , paris' law , fracture mechanics , alloy , chemistry , physics , organic chemistry , astrobiology
— The nucleation and growth of small naturally initiated cracks have been investigated on Ti 6 Al 4V alloys, with bimodal or globular microstructures. Tests have been performed in air at a stress amplitude near 0.75 of the yield stress. The influence of microstructure on fatigue damage is described and the differences in fatigue life of some titanium alloys are explained. The effect of microstructure on fatigue resistance is mainly related to the early stages of damage including initiation and small crack growth. Coalescence processes favoured by a high density of initiated surface microcracks in fine α grain material, or rapid initiation of large cracks in coarse α colonies, explains low fatigue resistance or lifetime scattering in globular alloys. Small crack growth retardation due to α/β barriers associated with a low surface crack density, limiting coalescence processes, explains the highest resistance of bimodal structures.