Equal-channel angular pressing of an Al-6061 metal matrix composite

An Al-6061 metal matrix composite, reinforced with 10 vol % Al2O3 particulates, was subjected to equal-channel angular (ECA) pressing at room temperature to a total strain of similar to 5. It is shown that the intense plastic straining introduced by ECA pressing reduces the grain size from similar to 35 mu m to similar to 1 mu m and this leads to an increase in the microhardness measured at room temperature. Inspection revealed some limit cracking of the larger Al2O3 particulates as a consequence of the ECA pressing. Tensile testing after ECA pressing gave a maximum ductility of similar to 235% at a temperature of 853 K when testing at strain rates from similar to 10(-4) to similar to 10(-3) s(-1). It is suggested that high strain rate superplasticity is not achieved in this material after ECA pressing due to the presence of relatively large Al2O3 particulates. (C) 2000 Kluwer Academic Publishers.