HVEM in situ studies of strain localization in Al-Li alloys

Conference · · TMS (The Metallurgical Society) Paper Selection; (USA)

OSTI ID:5442617

Kenik, E A ^[1]

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1. Oak Ridge National Laboratory, TN (USA)

Aluminum-lithium alloys are attractive on strength/weight and strength/modulus bases. However, in the hardened state, these alloys exhibit embrittlement and intergranular failure. Precipitate free zones (PFZs) at grain boundaries are generally blamed for the poor mechanical properties. In situ deformation studies in an HVEM permit the observation of dislocation motion in the matrix and the PFZ. Strain localization in both regions has been studied. Dislocations from shear bands enter the PFZs and cross-slip along the PFZ, trailing segments pinned at the PFZ-matrix boundary. Successive dislocations produce a dislocation wall at this boundary with significant misorientation ({approximately}10{degree}) between the matrix and its PFZ. Other microstructural observations of strain localization and their relation to embrittlement of A1-Li alloys are discussed.

• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 5442617
• Report Number(s): CONF-840909--
• Conference Information: Journal Name: TMS (The Metallurgical Society) Paper Selection; (USA) Journal Volume: 56
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
ALUMINIUM ALLOYS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DEFORMATION
DISLOCATIONS
EMBRITTLEMENT
GRAIN BOUNDARIES
LINE DEFECTS
LITHIUM ALLOYS
MECHANICAL PROPERTIES
MICROSTRUCTURE
STRAINS
STRESS ANALYSIS