Technology

High-entropy materials (HEMs) are a groundbreaking class of advanced materials characterized by their unique chemical and microstructural complexity. Unlike traditional materials, which are often composed of one or two principal elements, HEMs contain five or more principal elements. These elements can be combined in equal amounts (equimolar composition) or in specific ratios (non-equimolar composition). This ability to fine-tune the composition enables HEMs to achieve a remarkable combination of properties, making them suitable for a wide range of advanced applications.

HEMs include:

High-Entropy Alloys (HEAs): Metallic elements that often form simple phases, such as face-centred cubic (FCC) and base-centred cubic (BCC). Common elements include aluminium (Al), cobalt (Co), chromium (Cr), iron (Fe), nickel (Ni), titanium (Ti), vanadium (V)
, and molybdenum (Mo).

High-Entropy Ceramics (HECs): Non-metallic compounds combined to form a single-phase structure. Typical elements include zirconium (Zr), hafnium (Hf), titanium (Ti), niobium (Nb), and tantalum (Ta).

High-Entropy Oxides (HEOs): Complex oxides containing multiple metal elements. Common elements include magnesium (Mg), nickel (Ni), cobalt (Co), copper (Cu), and zinc (Zn).

High-Entropy Carbides/Nitrides: Materials composed of multiple metal carbides or nitrides. Typical elements include tungsten (W) , titanium (Ti), zirconium (Zr), hafnium (Hf), niobium (Nb), and tantalum (Ta).