Macro- and Microstructure of In Situ Composites Prepared by Friction Stir Processing of AA5056 Admixed with Copper Powders

Valery Rubtsov; Andrey Chumaevskii; Anastasija Gusarova; Evgeny Knyazhev; Denis Gurianov; Anna Zykova; Tatiana Kalashnikova; Andrey Cheremnov; Nikolai Savchenko; Andrey Vorontsov; Veronika Utyaganova; Evgeny Kolubaev; Sergei Tarasov

doi:10.3390/ma16031070

Macro- and Microstructure of In Situ Composites Prepared by Friction Stir Processing of AA5056 Admixed with Copper Powders

Materials (Basel). 2023 Jan 26;16(3):1070. doi: 10.3390/ma16031070.

Affiliation

¹ Institute of Strength Physics and Materials Science, Siberian Branch of Russian Academy of Sciences, 634055 Tomsk, Russia.

Abstract

This paper is devoted to using multi-pass friction stir processing (FSP) for admixing 1.5 to 30 vol.% copper powders into an AA5056 matrix for the in situ fabrication of a composite alloy reinforced by Al-Cu intermetallic compounds (IMC). Macrostructurally inhomogeneous stir zones have been obtained after the first FSP passes, the homogeneity of which was improved with the following FSP passes. As a result of stirring the plasticized AA5056, the initial copper particle agglomerates were compacted into large copper particles, which were then simultaneously saturated by aluminum. Microstructural investigations showed that various phases such as α-Al(Cu), α-Cu(Al) solid solutions, Cu₃Al and CuAl IMCs, as well as both S and S'-Al₂CuMg precipitates have been detected in the AA5056/Cu stir zone, depending upon the concentration of copper and the number of FSP passes. The number of IMCs increased with the number of FSP passes, enhancing microhardness by 50-55%. The effect of multipass FSP on tensile strength, yield stress and strain-to-fracture was analyzed.

Keywords: copper powder; dissimilar; friction stir processing; intermetallic compounds; mechanical properties; metal matrix composites; solid solution; structural phase state.

Grants and funding

This research was funded by the Russian Federation Government under research assignment for ISPMS SB RAS. project No FWRW-2022-0004 and project No FWRW-2021-0012.