Aravind Ra, Saravanan G
This paper examines the effects of multi-pass friction stir processing (FSP) on the microstructure, mechanical properties, tribology, and corrosion performance of AA6061 reinforced with AlFeCrCuMnNi high-entropy alloy (HEA) particles. Unlike previous studies, this research explores the use of multi-pass FSP (1, 2, and 3 passes) to embed HEA particles in situ and enhance these properties. Microstructural analysis revealed significant grain refinement, reducing the grain size to 2.43 μm after 3-passes, with a uniform distribution of grains and particles. The ultimate tensile strength (UTS) increased by 21 %, from 274.7 MPa (base metal) to 332.9 MPa, and elongation improved from 22 % to 32.7 %. Hardness nearly doubled, rising from 89 HV to 134 HV after three passes. Tribological testing showed reduced wear and friction, with the 3-pass composite demonstrating the best wear resistance. Additionally, corrosion resistance improved, with I corr decreasing by 58 %, from 7.683 × 10 −3 A/cm 2 (1-pass) to 3.264 × 10 −3 A/cm 2 (3-pass), and E corr shifting to a lower value of −0.86 V. These findings suggest that multi-pass FSP has significant potential to enhance the mechanical, wear, and corrosion properties of AA6061/HEA composites, offering promising opportunities for application in the automotive, aerospace, and marine industries, thus making it a valuable addition to surface composite processing.