Marvellous mixtures of metals

An alloy is defined as any substance formed from a mixture of chemical elements, at least one component of which is a metal: all alloys look and behave like metals, but their physical properties and therefore their applications vary enormously. All conventional alloys have one major component, which is always a metal and is known as the base or primary metal, and one or more minor ones. They are now integral to our everyday life. 

The theoretical idea of making complex alloys from many different elements was being tossed around in metallurgical circles in the 1970s and 80s but it took a decade or so for this idea to turn into a practical reality. Many multi-element alloys have now been developed and, perhaps counter-intuitively, they are often able to form single, stable, homogeneous phases. Although five elements are typical (and some researchers class four-element alloys as HEAs), much more complex combinations are possible. One group in China has produced HEA nanoparticles composed of equal proportions of no less than 17 disparate metals.