Nanotech metallurgy (also called nanotechnology enabled metallurgy, or nanometallurgy) is an emerging interdisciplinary domain of materials science and engineering (especially metallurgy), manufacturing, and nanoscience and engineering to study how nanophases (both ex situ and in situ) can be applied to significantly improve the processing/manufacturing, micro/nano-structures, and physical/chemical/mechanical behaviors of metals and alloys. This definition was first proposed by Xiaochun Li at the University of California, Los Angeles in 2018.
High performance metals and alloys offer potential to improve energy efficiency and system performance. While conventional metallurgical methods have reached certain limits, nanotech metallurgy has the potential to break the traditional barriers in the metals processing and manufacturing technologies. It has a wider scientific and technological reach beyond the concept of metal matrix nanocomposites (MMNCs), as the study of MMNCs normally focuses on how nanoparticles (generally of high volume fractions) are used to tune material properties only. With the development of more scalable methods of nanophase synthesis, incorporation, and dispersion for mass manufacturing, the metals and alloys produced by nanotech metallurgy are becoming more and more economical. Recently the discovery of a nanoparticle self-dispersion and stabilization mechanism in molten metals gives a scientific and technical foundation for scalable manufacturing in nanotech metallurgy.
Nanotech metallurgy covers research areas such as nanophase effects on processing/manufacturing, materials properties (e.g. mechanical, physical and chemical properties), synthesis and production of nanophases (both in situ and ex situ), interaction between nanophases and molten metal, solidification, and thermomechanical processing of metals containing nanophases.
Nanophases can be effectively used to tune microstructures of metals and alloys during solidification and thermomechanical deformation, to control recrystallization at elevated temperatures, and to break traditional metallurgical barriers, thus creating exciting new spaces in processing and manufacturing, such as in casting, thermoplastic deformation, welding/joining, heat treatment, and machining, etc..
Nanophases have significant effects on mechanical, physical and chemical properties of metals. As compared with conventional metal matrix composites (MMCs) that are reinforced by micro-scale phases, the addition of nanophases is promising to overcome many disadvantages of MMCs such as poor ductility, machinability and low fracture toughness. For example, a super-strong but lightweight metal with extremely high specific strength and modulus was developed by disperse ceramic silicon carbide nanoparticles in magnesium.
Nanotech metallurgy covers the synthesis, production and incorporation of nanophases (e.g. nanoparticles, nanowires, nanosheets, carbon nanotubes (CNTs), graphene, etc.). To utilize the cutting edge nanotechnology to metallurgy, the scalability and cost of the nanophases are the major concerning factors to evaluate the feasibility. It is worth to mention that, with the rapid development of nanophase synthesis, production, incorporation, and dispersion, the cost of nanophases are becoming increasingly economical for metallurgy. Recent studies (e.g. molten salt reaction, in-situ reaction etc.) on molten salt based nanophase synthesis and incorporation indicatefurther ways to reduce the cost of nanophases and open up wider applications
The interactions between nanophases and molten metal include wetting, incorporation, mixing and dispersion.
Researchers have utilized the nanoparticles to refine the grain for different alloys(e.g. Al alloy, Mg alloy, etc.) during solidification including casting, welding, 3D printing, etc. They can modify the grain size by serving as heterogeneous nucleation site or inhibiting grain growth during solidification. Nanoparticles can help to refine the secondary phase as well.
Nanotech metallurgy can be applied to a wide range applications including automobile, sports, biomedical, electrical and electronics, aerospace, and defense s, etc.