Flow processes at low temperatures in ultrafine-grained aluminum

Chinh, Nguyen Q., Szommer, Péter, Csanádi, Tamás and Langdon, Terence G. (2006) Flow processes at low temperatures in ultrafine-grained aluminum. Materials Science and Engineering: A, 434 (1-2), 326-334. (doi:10.1016/j.msea.2006.07.014).

Abstract

Experiments were conducted to evaluate the flow behavior of pure aluminum at low temperatures. Samples were processed by equal-channel angular pressing (ECAP) to give a grain size of ~1.2 ?m and compression samples were cut from the as-pressed billets and tested over a range of strain rates at temperatures up to 473 K. The results show the occurrence of steady-state flow in these highly deformed samples and a detailed analysis gives a low strain rate sensitivity and an activation energy similar to the value for grain boundary diffusion. By using depth-sensing indentation testing and atomic force microscopy, it is shown that grain boundary sliding occurs in this material at low temperatures. This result is attributed to the presence of high-energy non-equilibrium boundaries in the severely deformed samples.

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Contributors

Author: Terence G. Langdon

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