SEDL / STP / STP733-EB / STP33421S

Microstructural Origin of Flutes and Their Use in Distinguishing Striationless Fatigue Cleavage from Stress-Corrosion Cracking in Titanium Alloys

Meyn, DA
Metallurgists Naval Research Laboratory, Washington, D.C.,

Brooks, EJ
Metallurgists Naval Research Laboratory, Washington, D.C.,

Pages: 27    Published: Jan 1981

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Abstract

Postfracture analysis does not always distinguish striationless low-stress fatigue from stress-corrosion cracking (SCC), since both are characterized by cleavage, together with other less distinct fracture modes. Studies of identical specimens of Ti-8Al-1Mo-1V broken under both conditions suggest that the presence of certain microplastic fracture features called flutes may be uniquely characteristic of SCC, and absent from low-stress striationless fatigue fractures. Some new observations concerning the microstructural origins of flutes verify that they arise from a tendency toward planar slip in α and α-β alloys and from the presence of multiple cleavage during crack propagation under certain circumstances, including SCC.