Effect of Friction Stir Processing on Microstructure and Mechanical Properties of AlSi10Mg Aluminum Alloy Produced by Selective Laser Melting

Abstract

Friction stir processing (FSP) was successfully applied to AlSi10Mg alloy produced by selective laser melting. The microstructure, microhardness, and room-temperature tensile property of the FSPed AlSi10Mg alloy were investigated. The results showed that FSP eliminated the pores of the AlSi10Mg alloy and achieved the microstructural refinement, homogenization, and densification. The grain size was refined from 13.6\xa0μm to 2.3\xa0μm, and relative density increased from 93.3% to 99.6%. An increase in rotation speed led to the enhancement in the density; however, it slightly affected the grain size in this study. The Si particles were homogenously dispersed in the Al matrix, which resulted in uniform distribution of microhardness. FSP led to the increase in the elongation of the AlSi10Mg alloy by 298%, while ultimate tensile strength decreased by only 8%. The Orowan and dislocation strengthening mechanisms were responsible for the loss of strength. FSP has the advantage of acquiring good ductility while maintaining high strength.