Nanophase materials are materials with a grain size in the 1 to 100 nm range. Nanophase materials exhibit greatly altered mechanical properties compared to their normal, large-grained counterparts with the same chemical composition. For example, nanophase metals are up to five (5) times harder than the normal materials. While nanophase metals generally become harder and more brittle, nanophase ceramics become more ductile. In a typical nanophase material, 10 to 50% of the atoms are in grain boundary regions.
Nanophase materials can be made using a number of methods. The two main methods involve consolidation of nanometer sized particles or the creation of small grains using mechanical attrition. For the first method, small particles are created using techniques such as inert gas condensation or through the use of chemical processing. In the second case, larger particles are milled for a long period of time to create a very small grain size.