Advances in friction stir processing of aluminum 2024: a review of nanoparticle-reinforced surface composites

Friction stir processing (FSP) is an innovative solid-state processing technique that enhances the microstructure and mechanical properties of metals. This technique is particularly advantageous for aluminum alloys, including aluminum 2024, which is widely used in aerospace and automotive applications due to its excellent strength-to-weight ratio and fatigue resistance. AA 2024 is characterized by its high strength, low density, and good fatigue resistance, making it suitable for critical applications. However, it also has limitations such as susceptibility to stress corrosion cracking and lower toughness compared to other aluminum alloys. FSP addresses these challenges by refining the microstructure, which can lead to improved mechanical properties. The process involves a rotating tool that generates heat due to friction and deformation while traversing across the material's surface, resulting in localized plastic deformation and stirring of the material without melting. This work aims to present a comprehensive review on nanoparticle-reinforced surface composites of AA 2024. In addition, different types of ceramic and carbonaceous nanoparticles used as reinforcements have also been discussed in this article. Furthermore, different types of reinforcement strategies used for nanoparticle reinforcement have also been discussed. The basic parameters that influence the properties of synthesized composites have been reviewed as well. This paper extensively examines the pros and cons of nanoparticle FSP studies that have been published over the years.