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In situ TEM observations of liquid metal embrittlement of Al single crystals in HG+3atm\%Ga

Authors Su, YJ
Wang, YB
Chu, WY
Issue Date 1998
Source Key engineering materials , v. 145-9, (Part 1&2), 1998, p. 1053-1058
Summary The change in dislocation configuration ahead of a loaded crack tip, before and after adsorbing Hg atoms, and the initiation of liquid-metal-induced nanocrack (LMIC) have been in-situ observed using a special TEM constant-deflection device. The results show that chemisorption of Hg atoms facilitates dislocation emission, multiplication and motion. A LMIC is initiated either in the dislocation free zone (DFZ) or at the crack tip when the chemisorption-facilitated local plasticity is developed to a critical level. A new mechanism of liquid metal embrittlement (LME) is accordingly proposed that chemisorption of Hg atoms reduces the surface energy, leading to reduction in both the critical stress intensity factor for dislocation emission and the resistance to dislocation motion. Consequently, the plastic work, gamma(p), and the fracture toughness, K-IC, are decreased and the samples fracture in a brittle mode.
Note This work is partially supported by the National Natural Science Foundation of China and partially supported by the Hong Kong Research Grants Council through RGC grant HKUST819/96E.
ISSN 1013-9826
Language English
Format Article
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