Effect of heat input in dissimilar friction stir welding of A390-10 wt.% SiC composite–AA2024 aluminum alloy

Abstract

This study investigates the impact of heat input, generated during friction stir welding, on the microstructure, mechanical properties, and corrosion resistance of dissimilar joints between A390-10 wt.% SiC composite and AA2024-T6 aluminum alloy. Welds were created using two rotational speeds: 600 rpm and 1600 rpm, while maintaining a constant traverse speed of 60 mm/min and employing a triangular pin tool. The results reveal that increasing the heat input from 125 to 354 J/mm leads to enhanced mixing in the stir zone, resulting in the formation of a layered structure. The stir zone area increases by 23% with the rise in heat input from 125 to 354 J/mm. Moreover, as the heat input and plastic strain in the stir zone increase, the particle size decreases by 31%, and their distribution becomes more uniform. Furthermore, an increase in heat input leads to the formation of coarser precipitates and particles on both the advancing and retreating sides, regardless of the type of precipitates formed. Conversely, reducing the heat input from 354 to 125 J/mm results in achieving maximum hardness (165.3 ± 2.3 HV0.1), yield strength (410.3 ± 11.3 MPa), ultimate tensile strength (514.5 ± 10.4 MPa), and minimum corrosion rate (0.41 mm/year).