Abstract
Stainless steel particulates were chosen as alternatives to ceramic particles to improve particle-matrix bonding, toughness, and performance of aluminum metal matrix composites. A multi-pass friction stir processing route was utilized for the development of AA6061/316 stainless steel reinforced composites by varying the number of tool passes (1–4). Detailed microstructure analysis, corrosion, hardness, wear, tensile, and impact toughness behaviors of the developed composites were studied. An increment in the number of tool passes (1–4) did not cause a particle-matrix reaction or alter the presence of inherent Mg2Si, Al, and ferrous phases in the composites. The progressive increment in the tool passes significantly enhanced the dislocation density, grain refinement, particle refinement (36.4–22.4 μm), and dispersion within the composite's structure due to the successive rotating tool-induced high straining and plastic deformation, dynamic recrystallization, and Zener pinning phenomena. The successive tool pass-induced microstructure improved the microhardness value (129–146 HV), tensile strength (163–241 MPa), impact toughness (5.7 ± 0.1–11.35 ± 0.1 J/cm3), and corrosion resistance of the composite while the wear rate (0.37–0.11 mm3/Nm) and the mean friction coefficient (0.37 ± 0.1–0.21 ± 0.1) of the composite were significantly reduced as the number of the tool passes was increased. The 4-pass friction stir processing technique is thus recommended for the development of AA6061/316 stainless steel reinforced composites.
•Stainless steel particulates were chosen as alternatives to ceramic particles during FSP.•The multi-pass friction stir processing (MPFSP) method was deployed for the development of the AA6061/316 stainless steel reinforced composites.•Particle refinement and homogenized dispersion were enhanced by the increment in the level of the tool pass as the average particle sizes of 36.4, 29.8, and 22.4 μm were produced after the 1st, 2nd, and 4th tool passes respectively due to the successive plastic deformation and high strain.•The tensile strengths of the composites were 163, 205, and 228 MPa after the 1st, 2nd, and 4th tool passes respectively owing to the better material flow, particle fragmentation-dispersion, retained strengthening Mg2Si phase, grain refinement, and improved dislocation density.•A change in the level of the tool pass slightly alters the fracture locations of the AA6061/316 stainless steel reinforced composite after the tensile tests owing to the successive material flow impact on the microstructure of the composites.•The transition from mixed wear behavior to predominant abrasive wear occurred as the level of the tool pass was raised from 1 to 4.