Study on New Extrusion Route of Equal Channel Angular Processing in High Purity Aluminium

Abstract

The new extrusion route of ECAP which is called route 135 was put forward in this paper. The grain refinement of the traditional extrusion route BCand the new route of ECAP process in 99.9995% (5N5) high purity aluminum was compared using a die with a channel-intersection angle 90°. It was found through experiment that, the grain was very coarse in the cast ingot of 5N5 high purity aluminum, and the average grain size is about 60mm. High purity aluminum processed by one pass ECAP was refined notably, and average grain size is about 1000 μm. After two ECAP passes, the average grain size is 200μm with route BC, while it is less than 50μm with route 135. The refinement of two passes of route 135 is equivalent to the refinement of eight passes of route BC. It indicates that the route 135 is more effective than route BC. TEM micrograph of 5N5 high purity Al with different ECAP pass under route BCand route 135 was studied.