Hybrid Manufacturing of Aluminum Metal Matrix Composites: Enhancing Properties through Stir Casting and Friction Stir Metal Deposition

Abstract

This study investigates the fabrication of aluminum metal matrix composites (AMCs) reinforced with zirconia (ZrO<inf>2</inf>) using a hybrid technique combining conventional stir casting and friction stir metal deposition (FSMD). Composites with ZrO<inf>2</inf> content ranging from 2.5 to 5 wt.% were produced, and a systematic comparison was conducted between specimens fabricated solely by stir casting and those subjected to the hybrid route. Characterization included microstructural evaluation, density, microhardness, phase analysis, and fretting wear performance. FSMD processing resulted in refined and homogenized microstructures, reducing average grain sizes significantly from 33.8 ± 11.1 to 6.5 ± 1.6 µm for 2.5 wt.% ZrO<inf>2</inf> and from 39.9 ± 12.5 to 9.8 ± 2.3 µm for 5 wt.% ZrO<inf>2</inf> composites. Enhanced dispersion of ZrO<inf>2</inf> and improved metallurgical bonding in FSMD samples led to superior mechanical properties, including increased microhardness (72.8 versus 69 HV) and reduced wear rates. Additionally, tensile strength and ductility were markedly improved in FSMD samples, achieving 262 MPa and 7.6% elongation, respectively, compared to 221 MPa and 3.8% for stir-cast composites at 5 wt.% ZrO<inf>2</inf>. These enhancements are attributed to dynamic recrystallization, grain boundary strengthening, and improved particle-matrix interface integrity. The results underscore FSMD’s potential to produce high-performance AMCs for critical applications in aerospace, automotive, and biomedical fields. © 2025 Elsevier B.V., All rights reserved.