Structural Disorder as Control of Transport Properties in Metallic Alloys

Structural disorder is ubiquitous for a large class of metallic alloys. Such an alloy’s transport properties are highly susceptible to change when the disorder is modified. A first-principle method has been developed for modeling of disorders in metallic alloys. In this approach, an alloy specimen is regarded as a randomly closepacked mixture of a population of nanocrystallites and constituent atoms in glassy state. The disorder is then represented by the size distribution function of the nanocrystallites. Under sustained exposure to thermal, stress, nuclear or chemical forcing at an elevated temperature, the distribution function becomes modified, and this process is predictable for a given forcing condition, and thus controllable. Transport of excitations is affected by the detail of the distribution function, making it possible to control transport properties, all at a fixed alloy composition. The modeling and experimental support will be presented.