Advancements in metal additive manufacturing: opportunities, limitations, impact on properties, and potential solutions: a review

Nowadays, additive manufacturing (AM) is a leading digital manufacturing method because of its unprecedented levels of customization and freedom in design. There is a growing interest of Metal Additive Manufacturing (MAM) in critical-performance applications, especially in the aerospace industry. Excellent surface finish and microstructure uniformity are required for higher fatigue resistance, making components with poor surface finish unacceptable for such applications. The present paper offers an in-depth overview of the most recent studies in different materials produced through the selected AM methods. Emphasis is also placed on various metals and alloys, highlighting their special benefits, and resolving associated challenges. Achievable surface quality and mechanical properties via additive manufacturing technologies, as well as practical applications in aerospace, spacecraft, medical implants, and automotive parts, are covered in the discussions. The impacts of defects, processing parameters, and microstructure on mechanical properties of components produced, primarily Powder Bed Fusion (PBF) and Directed Energy Deposition (DED) are thoroughly discussed. A summary of current discoveries in post-processing such as surface hardening treatment processes required for optimizing surface qualities and mechanical properties of these novel structures is given. Furthermore, emerging technologies for best performing parameters along with potential prospects in metal AM for research and development are provided. In its entirety, the results of this article enable researchers to improve the customization, personalization, and sustainability of aerospace structures as well as high-performance systems, thus, promoting reduction of waste, conservation of materials, and overall efficiency.