One of the key research topics pursued by metal material researchers is how to engineer metal alloys that are stronger and elongate easily. Alloys are made by blending additional elements with major metals to improve their strength, flexibility and other critical properties and are deployed across industrial settings. In contrast, high-entropy alloys are formed by mixing relatively equal proportions of multiple elements, which theoretically opens them up to unlimited possibilities in the type of alloys that can be fabricated. The choice of elements and their contents can be easily monitored and controlled to deliver improved strength, malleability and corrosion resistance as well as electromagnetic and thermal properties.

High-entropy alloys come in single-phase forms, indicating that the structure or organization of their materials, the size of the crystalline particles, and shapes are all identical. Maintaining single phase forms requires the addition of such expensive elements as cobalt or chrome, and this makes it challenging to produce these alloys at competitive prices.

In June 2020, the Structural Nano Metals Processing Laboratory directed by professor Hyoung Seop Kim at the Department of Materials Science & Engineering, POSTECH, developed a hetero-structured high-entropy alloy that maximized its heterogeneity. What they did is blend iron and copper, which do not ordinarily mix just as oil and water, with the elements that bind them. Such hetero-structured alloys contain inner structures or organizations, crystalline particle shapes and sizes that are not identical but differ depending on their position.

As the 4^th Industrial Revolution is emerging as the key agenda of the 21^st century, there is an immense shift in the research of metal materials. Notably, physical experimentation is becoming more integrated with AI-based machine learning and computer simulation. The Lab is also leveraging such cutting-edge research methodologies to establish ‘multi scale integrative modeling’ which supports analyses from the nano and micro to the macro scale.

In particular, the Structural Nano Metals Processing Lab is Korea’s first to initiate research on high-entropy alloys and is known for its global competitiveness. The Lab plans to make further progress on 3D printing and machine learning. Presently, researchers at the Lab are able to make use of simulation, modeling, and even machine learning in addition to casting and rolling, 3D printing, severe plastic deformation, micro-sized structures, and ultra-low temperature machine experiments which deploy nitrogen liquids at – 196. It is even possible to predict the mechanical, thermal, electrical, and chemical characteristics of the target material prior to experimentation and to accurately mimic these characteristics in so doing.

The research conducted by the Lab on the hetero-structured high-entropy alloy based on Cu and Fe has broken the common notion that ‘high-entropy alloys are expensive’ and is contributing to the commercialization of high-entropy alloys as a result. Researchers at the Lab firmly believe that the combination of simulation and machine learning technology alone will not guarantee meaningful outcomes unless they are accompanied by theory and substance. It is with this philosophy that the Lab aspires to broaden the horizon in the study of novel metal materials.