Aluminum Alloy Chips Recycling using Friction Stir Consolidation

The purpose of this paper is to develop AA5052 aluminum alloy solid disc from machining wastes via friction stir consolidation (FSC) process & optimize its parameters: die rotational speed, pre-compact aspect ratio and processing time. At first, the required dedicated tooling is designed and built. Then, solid discs are fabricated from AA5052 aluminum alloy chips using FSC process. Taguchi L9 orthogonal array is used to analyze and optimize the process. Experimental parameters and their levels considered are rotational speed (315, 400 and 500 rpm), pre-compact aspect ratio (25.4/7, 25.4/5 and 25.4/3) and processing time (30, 45 and 60 sec). Using standard tests, compressive strength, hardness and microstructure of the consolidated solid disc are evaluated. The results reveal that solid discs are successfully fabricated using FSC using dedicated tooling, and rotational speed (500 rpm), pre-compact aspect ratio (25.4/3) and processing time (60 sec) are optimal processing conditions. Microstructure examination of the solid disc shows finer and fully recrystallized grains in axial cross section orientation. Moreover, the results show compressive strength and hardness of the solid disc are comparable to that of forged or cast disc and suitable for most engineering structural applications.