INFLUENCE OF DIE ANGLES ON THE MICROHARDNESS OF ALUMINUM ALLOY PROCESSED BY EQUAL CHANNEL ANGULAR PRESSING

The die geometry has a massive effect on the plastic deformation behavior during pressing of material processed by equal channel angular pressing (ECAP) method; subsequently the properties of the processed material are strongly dependent on the die design. Two categories of designed and manufactured dies are used for equal channel angular pressing, a 1200 sharp angle ((Psi) = 0^0) and a 90^0 round–cornered (Y = 20^0) dies. This produce strain per pass through both dies of ~0.7 and ~1.05 respectively. The microhardness is developed in Al-Si alloy during ECAP using route BC. The microhardness is increased by a factor of 1.5 after only 1 pressing for both dies. The microhardness increases slightly up to 8 passes, to increase by a factor of ~2.6 through the 1200 sharp angle die, while it is increased by a factor of ~3 after 8 passes by using the 900 roundcornered die, compared to the microhardness of the cast workpiece. In addition, the microhardness values are essentially identical across each ECA pressed workpiece on both X and Y planes.