Dr. Rahul Kumar received his PhD in materials engineering in 2022 from Tallinn University of Technology (Estonia) and currently works there as a researcher at the “Research Laboratory of Tribology and Materials Testing”. During this time, Dr. Kumar has engaged in numerous EU-funded international projects and collaborated with prestigious research centers, including the “Austrian Competence Centre for Tribology” (Austria) and “Łukasiewicz Research Network—The Institute for Sustainable Technologies” (Poland). His expertise spans the development and testing of polymer, metal, and ceramic materials, including their functional composites. His primary research interests encompass high-temperature tribology, friction and wear in dry contacts, surface engineering for friction and wear control, green tribology, and multifunctional tribomaterials developed using powder metallurgy and additive manufacturing. Dr. Kumar has presented his research at reputed international conferences, such as the Leeds–Lyon Symposium 2019, Wear of Materials 2021, NordTrib 2022, etc. Currently, his research focuses on the sustainable recycling of hard metals for tribological fitness, alongside 3D printing of nature-inspired biomaterials to tailor mechanical and frictional functionalities. He is an active associate member of The Institution of Engineers (India).