Recent advances in surface modification of metals and alloys: enhancing material protection and performance in challenging environments

Surface modification processes, categorized as impact-based, thermal/laser-based, and hybrid, are gaining momentum as innovative and efficient strategies to improve fatigue strength, hardness, corrosion resistance, and wear properties of various structural parts produced via additive manufacturing. These AM-produced components require superior tribological and surface roughness properties compared to traditional processes. With the exciting advancements in manufacturing of mechanical components, digital manufacturing is at the forefront to provide an economic approach to minimizing production cost and time. However, components fabricated via AM require post-surface treatments to tackle surface-related issues like surface roughness, porosity, and residual stresses, thereby enhancing performance and sustainability across aerospace, nuclear, space, and automotive industries. Therefore, this study reviews various methods used to improve surface properties of current and next-generation AM fabricated components made from various metallic AM alloys. Various studies have shown that surface modification methods provide special advantages in terms of efficiency, control, and flexibility. Finally, the difficulties and opportunities to further enhance the mechanical properties by various optimization techniques are outlined and discussed. Our findings show that the maturity levels of various surface modification processes differ, and some have made their way into the aerospace and automotive industries. In contrast, others have not transitioned successfully to industrial applications due to challenges such as scalability limitations, high costs, restricted accessibility for complex additive manufacturing (AM) geometries, and the absence of standardized AM-specific data. The critical discussions presented in this paper are intended to benefit academic and research communities working in additive manufacturing and mechanical surface treatment.