Challenges and Future Trends in High and Medium Entropy Alloys for Biomedical Applications: Systematic Review

This article presents a systematic review of high and medium entropy alloys (HEA and MEA) for biomedical applications, also known as BioHEA, highlighting their biocompatibility and superior mechanical properties. The study methodology included a systematic review using the Proknow-C process, as well as a bibliometric network analysis and visualization using VOSviewer software (version 1.6.20). The results show increasing research on BioHEA, especially in China. Synthesis methods and mechanical properties were discussed, emphasizing the importance of low Young’s modulus, high hardness, and wear resistance for orthopedic applications. In addition, most of the reported alloys were found to have a body-centered cubic (bcc) microstructure. A distinctive aspect of this work is the discussion of the biological properties of the elements used in BioHEA, which include biocompatibility, genotoxicity, carcinogenicity, mutagenicity, cytotoxicity, and corrosivity. From this, elements that present potential risks and should not be used in biomedical applications were identified, as well as those that are most recommended and highlighted. In addition, future trends are discussed, such as the implementation of innovative processing routes like the Direct Ink Writing (DIW) 3D printing method, and the use of Machine Learning to optimize key properties.