Change in dislocation configuration ahead of a loaded crack tip of Al alloy 7075 (UNS A97075) before and after adsorbing Hg-3at% Ga atoms, and initiation of liquid-metal-induced microcracking have been observed in a transmission electron microscope (TEM) using a special TEM constant-deflection device with precracked foil. Results showed that chemisorption of liquid metal atoms can facilitate dislocation emission multiplication and motion. A microcrack initiated in the dislocation free zone or at the crack tip and propagated by a cleavage mode when the chemisorption-facilitated local plasticity developed to a critical level.

Subject
Foil, Dislocation, Liquid metals, Microcracks, Atmosphere, Transmission electron microscopy, Crack initiation, Crack propagation, Motion, Stress cracking, Equipment, Plastic deformation, Liquid metal embrittlement
Keywords:
Al 7075, dislocation emission, liquid metal embrittlement, transmission electron microscopy
NACE International
1999
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