Hydrogen embrittlement in a Mg-Al alloy
| Autor: | D. G. Chakrapani, E. N. Pugh |
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| Rok vydání: | 1976 |
| Předmět: | |
| Zdroj: | Metallurgical Transactions A. 7:173-178 |
| ISSN: | 2379-0180 0360-2133 |
| DOI: | 10.1007/bf02644454 |
| Popis: | Experiments are described which demonstrate that a Mg-7.5 wt pct Al alloy is embrittled by both cathodically-generated and gaseous hydrogen. Immersion of unstressed specimens in an aqueous NaCl-K2CrO4 solution is shown to lead to absorption of hydrogen and to a form of internal hydrogen embrittlement similar to that observed in BCC metals. Thus embrittlement was manifested by loss of ductility in tensile tests and by cleavage-like fracture surfaces; vacuum annealing after immersion led to a reduction in hydrogen concentration and to a partial recovery of ductility; and embrittlement was not observed at high strain rates. Embrittled specimens also exhibited delayed failure in both constant-load tensile tests and constant-deflection bend tests. In a second series of experiments, slow crack growth was observed when edge-notched tensile specimens were stressed in ~ lpsig (~ 6.9 × 103 N/m2) dry hydrogen; the fracture surfaces were again cleavage-like in appearance. The significance of these observations is discussed in relation to the stress-corrosion failure of this alloy. |
| Databáze: | OpenAIRE |
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