Processing of eutectic Zn-5% Al alloy by equal-channel angular pressing

Multi-pass equal-channel angular pressing (ECAP) was applied to the eutectic Zn-5% Al alloy as a first step in the examination of the binary Zn-Al alloy system by using two different processing routes: route A, where the sample is pressed repetitively through the die without rotation, and route C, where the sample is rotated by 180degrees after each pass. A "three-block die" for ECAP was designed and manufactured. Evolution of hardness was investigated and microstructural changes were noted during ECAP. Variations in the applied load during ECAP of the alloy were analyzed, and the relationship between maximum load and hardness was discussed. It was observed that the equiaxed grain structure of the as-received alloy completely disappeared and instead a banded structure was formed during the ECAP process. Hardness of the alloy decreased with increasing number of passes for both processing routes. The applied load during ECAP increased up to a maximum value, and this was followed by a decrease until the end of pressing in all processing conditions. The maximum load required for the ECAP of the alloy decreased for both routes with increasing number of passes. It was observed that the hardness and the maximum load showed similar trends with number of passes for both processing routes. (C) 2004 Elsevier B.V. All rights reserved.