Influence of tool rotational speed on microstructure, mechanical strength, and wear behavior of AA7075 matrix composites via deformation-driven metallurgy

Abstract

The pursuit of high-performance aluminum matrix composites (AMCs) for advanced engineering applications has driven interest in novel fabrication techniques. This study explores the deformation-driven metallurgy (DDM) method for producing AA7075-Al₂O₃ composites, shedding light on how tool rotational speed influences their microstructure, mechanical properties, and wear resistance. Unlike conventional melt-based methods, DDM leverages severe plastic deformation to achieve unique material characteristics. A standout finding of this research is the exceptional uniformity and refinement of Al₂O₃ particles (7.3 ± 1.3 µm) achieved at 800 rpm, along with a remarkable ultimate tensile strength of 613.3 ± 12.1 MPa—significantly surpassing prior reports for similar composites. Interestingly, while increasing rotational speed to 1400 rpm resulted in grain coarsening from 5.4 ± 0.9 µm to 19.1 ± 0.4 µm, the process maintained a random texture across all samples. The composite fabricated at 800 rpm also exhibited superior hardness (202.05 ± 3.32 HV0.1) and the lowest wear rate (4.8 ± 0.2 µg/m), making it a promising candidate for applications requiring high strength and wear resistance. This study not only demonstrates the effectiveness of DDM in producing high-performance composites but also highlights the critical role of process parameters in tailoring material properties, offering insights distinct from traditional fabrication approaches.