Examination of microstructure and mechanical properties of direct additive recycling for Al-Mg-Mn alloy Machine chip waste

Abstract

In this study, the as-deposited microstructure and mechanical properties are examined for both the wrought strain hardened Al-Mg-Mn alloy (AA5083-H131) feedstock and the AA5083 machine chip waste feedstock processed with Additive Friction Stir Deposition (AFSD). Monotonic tensile and uniaxial fatigue experiments compared three specimen types: AA5083-H131 Wrought control, AA5083 AFSD-Recycled, and AA5083 AFSD-Solid bar. Tensile and fatigue results demonstrated comparable performance between the recycled material and wrought control. Experimental results indicate the thermo-mechanical processing of AFSD resulted in an exchange of strengthening mechanisms – replacing the strength of wrought material from strain-hardening to grain boundary strengthening from a refined as-deposited microstructure. Although strengthening mechanisms evolved in AA5083, the mechanical performance of the AFSD-Recycled material including improved fatigue performance over the wrought control samples illustrates the potential use of the AFSD process to reclaim waste machine chips into components or repairs while maintaining high mechanical performance requirements.