AlCoCrFeNi high-entropy alloy particle reinforced 5083Al matrix composites with fine grain structure fabricated by submerged friction stir processing

In the present work, 5083Al matrix composites reinforced by 10 vol% AlCoCrFeNi high-entropy alloy (HEA) particles were fabricated by submerged friction stir processing (SFSP). It was found that the fabricated composites consist of equiaxed fi ne grains with the mean size of 1.2 mu m due to dynamic recrystallization, particle stimulated nucleation (PSN) and shortened thermal cycle by water cooling. The HEA/5083Al interface showed a two-layer structure, the layer close to the HEA exhibited FCC + T phases with the thickness of approximately100 nm, and the other layer consisted of the Cr-depleted AlCoCrFeNi HEA particles in the size of roughly 100 nm. The SFSPed HEA/5083Al composites showed 25.1% higher yield stress (YS) and 31.9% higher ultimate tensile strength (UTS) in comparison with the base metal while maintaining acceptable ductility (18.9%). Grain refinement, geometrically necessary dislocations and load transfer effect can mainly be responsible for the improved strength. (C) 2020 Published by Elsevier B.V.