Microstructural evaluation of Re particle reinforced composite on aluminium surface by friction stir processing

The paper presents the results of friction stir processing (FSP) process of cast aluminium alloy AlSi9Mg. The studies included a modification of the microstructure in the grain refinement, elimination of voids and the production of composite material AlSi9Mg + Re. Rhenium is famous for its refractory character, high density as well as high hardness. It is well known as alloying element for improvement of strength, plasticity, weldability, reduction of the degree of recrystallization embrittlement mainly in W, Mo and Ni based alloys. Re is used in superalloys as a solid-solution strengthening alloying element and increasing corrosion resistance at high temperatures. Rhenium containing alloys have high electrical resistivity and refractory character. The modification was carried out single-and multiple runs. The results show significant fragmentation in the mixing microstructure, and a metallic continuity. Fragmentation in the mixing microstructure was confirmed by SEM research. The study revealed that mechanical alloying technology FSP allows to increase the hardness of the material. The ability to produce graded materials AlSi9Mg alloy matrix by frictional treatment is also indicated.