Effect of processing route on grain refinement and mechanical properties in equal channel angular pressing of aluminium alloy AA7068

Abstract

Influence of different processing routes on microstructure of aluminum alloy AA7068 during equal channel angular pressing (ECAP) up to four passes is investigated. Equalchannel angular pressing is one of the best severe plastic deformation methods to achieve ultra-fine grain structure by subjecting metal to an intense plastic strain through a simple shear. A significant amount of grain refinement as occurred by passing aluminium alloy samples through ECAP split die at 200°C temperature from first pass up to four passes with two different processing routes such as route A and route Bc. The experimental results revealed that out of two different processing routes, route Bc where the samples are rotated by an angle of 90° in the same direction after each pass, is able to achieve rapid microstructure evolution with a better grain refinement and an equiaxed microstructure as compared to that of route A. Mechanical properties such as hardness and tensile strengths of the ECAP processed samples via route A and route Bc are also revealed that route Bc is the optimum process parameter which induces better mechanical properties into the metal.