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, Journal Name: Materials Characterization Journal Issue: 1 Vol. 37; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

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