Micro-nano structure and characterization in the nugget zone of Al-Cu-Mg alloy under friction stir processing

Abstract

In this paper, the microstructure in the nugget zone of a friction-stir-processed Al-Cu-Mg alloy was analysed. There are the irregular bulk precipitates and micro-voids in the Al-Cu-Mg alloys. These precipitates were the compounds of Al-Cu system, and the size is less than 1 µm. In a local area, the homogeneous amorphous structure of Al-Cu system in some area of the nugget zone was also detected. The amorphous structure with a halo pattern has a structure characteristic of the long-range disorder. The formation of micro-nano and amorphous structure in the nugget zone could be attributed to the severe plastic deformation, breaking effect of stir tool, higher temperature gradient, hydrostatic pressure and shear stress and strain.

Influence of tool rotational speed on the microstructure and mechanical behavior of friction stir processed AA 7050 aluminum alloy

“…The literature includes research by various researchers on the evolution of the microstructure and mechanical behavior of aluminum-based alloys after FSP [15][16][17][18][19][20][21][22]. These investigations have demonstrated that FSP parameters such as tool geometry, tool rotation speed, and travel speed influence the microstructure and corresponding mechanical properties.…”