Vacuum fatigue fracture of Ti--6Al-4V
The fractography of structure-sensitive and structure-insensitive vacuum fatigue in fine grained Ti--6Al--4V was investigated using both scanning electron microscopy and transmission electron microscopy of replicas. It is shown that structure-sensitive fatigue of fine grained Ti--6Al--4V in vacuum takes place principally by basal or near-basal cleavage. It is likely that the cleavage is essentially noncyclic, and mechanically rather than environmentally induced. The structure-sensitive to structure-insensitive transition correspond with a cyclic plastic zone size intermediate between the minor and major dimensions of the elongated alpha grains. Cyclic crack growth was detached for structure-insensitive fatigue, as reported by others. (auth)
- Research Organization:
- Nationaal Lucht- en Ruimtevaartlaboratorium, Amsterdam (Netherlands)
- OSTI ID:
- 7311491
- Report Number(s):
- N-76-31340; NLR-MP-75006-U
- Country of Publication:
- United States
- Language:
- English
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