Volume 12 Issue 1 ( March 2025)

The effect of case thickness and die channel angle on the mechanical properties and microstructure of AA 5083 alloy processed by a novel equal channel angular rolling (ECAR) process using copper as the case material has been evaluated and reported. The copper sheets of different thicknesses (0.5 mm, 1.0 mm, and 1.5 mm) were used as casing on both the sides of the AA 5083 alloy. ECAR was processed at room temperature on alloy sheets of different thicknesses (2 mm, 3 mm, and 4 mm) using different dies with variation in channel angles (90°, 105° and 120°) in A-Route.In the ECAR process, the 'A-route' refers to a primary pathway through which the sheet is passed between rolls. The subsequent passes of the work material were performed in the same direction without rotating the work material. Four passes were given for the sheets of different thicknesses and the structural and mechanical properties were evaluated after each pass. The Vickers hardness property of the alloy increased with an increase in case thickness up to 1mm and beyond that, the hardness decreased. The hardness of a 3.0 mm thick sheet with 1.0 mm copper casing produced by a die with channel angle 90° has enhanced by approximately 150% from the 1st pass to the 4th pass. The tensile strength and yield strength of the alloy were enhanced by 42% and 228% respectively, and the grain size was reduced from 60 µm to 0.71µm after the first pass and to 0.42 µm after the fourth pass. The mechanical and structural properties obtained for a 3mm thick sheet with a 1mm copper casing are much superior to those obtained for other sheets. The novel ECAR process using copper casing resulted in improved mechanical properties, grain refinement and structural homogeneity because of the lower coefficient of friction between copper and steel than between aluminum and steel.

Keywords: Aluminum; SPD- Severe Plastic Deformation; ECAR- Equal Channel Angular Rolling; Microstructure; Copper Casing; Fractographic analysis; COF- Coefficient of friction