Abstract
ECAP (Equal-Channel Angular Pressing) can produce large strains in a billet without decreasing its original diameter or thickness and therefore is an attractive process for the production of alloys with fine grained microstructures. However, since the strain per pass through the die is not large in ECAP, about 10 passes are required to obtain a desired fine microstructure. In conventional ECAP, the pressed billet must be removed from the die and reinserted back for the next pressing cycle, making the ECAP process inefficient and difficult to control. The latter problem is eliminated in ECAP with a rotary die. Tests with an AC4C alloy have shown that ECAP processing up to 20 passes is possible without billet removal. After 10 passes, the AC4C alloy showed 2–3 μm grain sizes, which enhanced the tensile ductility at 723 K up to about 126%. The tensile specimens showed a smooth surface after testing.
