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 ∼5. It is shown that the intense plastic straining introduced by ECA pressing reduces the grain size from ∼35 μm to ∼1 μm 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 ∼235% at a temperature of 853 K when testing at strain rates from ∼10−4 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.