A study of (001) glide in [112] aluminium single crystals

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Abstract
[110](001) slip has been studied in [112] aluminium single crystals deformed in creep. Metallographic and microstructural observations were performed. At 150°C, the two primary {111} planes in a symmetrical orientation are activated. At 180-200°C, (001) starts being activated in some areas of the sample. The corresponding wavy slip traces indicate that slip is unstable on (001) and frequent cross-slip occurs between this plane and two {111} slip systems with low Schmid factors. In situ experiments in this temperature range show that screw dislocation motion on (001) is difficult. At 400°C and above, (001) slip becomes easy and straight traces are clearly visible. Two distinct dislocation substructures correspond to these different deformation modes. It is shown that (001) glide does not originate from the recombination of Lomer-Cottrell barriers, but dislocation multiplication takes place on this non-compact plane. The microscopic mechanism associated with (001) glide, and the importance of this slip mode in high-temperature deformation will be the subject of a second paper.