Manganese-Based Alloys: Advancements, Challenges and Future Directions in Metallurgical and Functional Applications

Manganese is a key transition metal essential to metallurgy, particularly for strengthening steel. Alloys of manganese including iron-manganese (Fe-Mn), manganese-aluminum (Mn-Al), manganese-titanium (Mn-Ti), and other multi-element systems are increasingly critical in biomedical, aerospace, energy, and marine industries. This review consolidates current knowledge, highlights research gaps, and charts future directions by examining Mn’s chemical and metallurgical properties, major alloy systems, mechanical and corrosion performance, and modern processing methods. In-depth case studies in automotive (TWIP steels), biomedical (biodegradable stents), and aerospace (high-entropy alloys) applications are presented to illustrate real-world performance. A comparative analysis of advanced manufacturing techniques, including Laser Powder Bed Fusion (L-PBF) and Directed Energy Deposition (DED), reveals the profound impact of processing on microstructure and properties. Drawing on over seventy recent studies, this work assesses how microstructure, phase transformations, and alloying behavior influence performance across structural, biodegradable, and functional applications. Despite notable progress, challenges persist in predicting corrosion, ensuring long-term biocompatibility, overcoming low-temperature brittleness, and mitigating the environmental impacts of manganese processing. A critical evaluation of the manganese lifecycle, from mining impacts to recycling challenges, underscores the need for sustainable practices. To address these challenges, we recommend advanced manufacturing for precise microstructural control, surface treatments to improve corrosion resistance, and computational modeling to predict performance. Future research should prioritize corrosion-resistant, biocompatible alloys, refine additive manufacturing for complex designs, gather long-term biocompatibility data, and improve recycling methods. Collaborative efforts integrating simulations, experimental validation, and sustainable practices will ultimately shape manganese’s role in future innovations.