Enhancing mechanical, and tribological properties of aluminum metal matrix composite reinforced with high entropy alloy using friction stir processing

A metal matrix composite was fabricated via friction stir processing (FSP) wherein the aluminium AA5083 series was strengthened through the integration of AlCoFeNiMn High Entropy Alloy (HEA) particle. The HEA powder used for FSP was prepared through high energy ball milling for 10 h, followed by annealing at 1273 K for an additional 10 h. The resulting powder had an average particle size of similar to 10 mu m and exhibited a dual-phase microstructure, consisting of FCC and BCC phases. The sample subjected to multiple passes of FSP (5 times) showed a uniform distribution of HEA particles within the aluminium matrix, with significantly improved bonding between the HEA particles and the matrix compared to the single-pass FSP treatment. Notably, the tensile test results indicated that the multi-pass friction stir processed (MFSPed) aluminium metal matrix composite (AMC) exhibited higher tensile strength (297 MPa) and elongation (12 %) than that of the single-pass friction stir processed (SFSPed) AMC with 252 MPa and 5.2 %, respectively. Moreover, the hardness of the MFSPed AMC increased to 105 HV, a remarkable 36 % improvement over the as received AA5083 series, which stood at 77 HV. The results from wear tests conducted on both SFSPed and MFSPed AMC samples demonstrated a reduction in the friction coefficient and wear rate when compared to the as received AA5083 series. These findings conclusively demonstrate the efficacy of HEA reinforcement in enhancing the surface hardness and wear resistance of the AMC.