Transmission electron microscopic investigation of hot-salt cracking in titanium alloys

Journal Article · Mon Jul 01 00:00:00 EDT 1996 · Materials Characterization

DOI:https://doi.org/10.1016/S1044-5803(96)00050-2· OSTI ID:409674

Toy, S M ^[1]

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1. Interscience Lab., Palo Alto, CA (United States)

New dislocation structures in Ti-8Al-1Mo-1V were observed after exposure to hot salt at 440 C for 1 h in a vacuum at 10{sup {minus}6}mm Hg. Dislocation sources were found to be associated with salt crystals or stain sites formerly occupied by salt. These dislocation sources are believed to be capable of generating a sufficient number of dislocations during dislocation pileup to nucleate cracks at grain boundaries, inside the grain or grain boundary precipitate. A stacking fault energy for Ti-8Al-1Mo-1V was calculated to be 15.4 erg cm{sup {minus}2}. This value indicated that the alloy had low stacking fault energy. This energy is consistent with the pileups, stacking faults, and complex networks observed. Dislocation structures observed for Ti-8Al-1Mo-1V and Ti-6Al-4V were similar at room temperature but not after exposure to hot salt. Metallurgical processing to control grain size and grain boundary precipitation could be beneficial in reducing hot-salt-cracking susceptibility of the titanium alloys investigated.

• OSTI ID: 409674
• Journal Information: Materials Characterization, Vol. 37, Issue 1; Other Information: PBD: Jul 1996
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
33 ADVANCED PROPULSION SYSTEMS
TITANIUM BASE ALLOYS
MICROSTRUCTURE
CORROSION
FRACTURE PROPERTIES
ALUMINIUM ALLOYS
MOLYBDENUM ALLOYS
VANADIUM ALLOYS
AEROSPACE INDUSTRY
MATERIALS
ENGINES
AIRCRAFT COMPONENTS
CHEMICAL COMPOSITION
STRESSES
SEAWATER
DISLOCATIONS
GRAIN BOUNDARIES
PRECIPITATION
STACKING FAULTS
GRAIN SIZE