Ultrafine-grained material is multi-crystalline material with an average grain size in
Micron (submicron structure; 100 nm to 1000 nm) and Nano (nano-structure;
Smaller than 100 nm). The fabrication of bulk ultrafine-grained materials has an
increasing role since this material tends to have better physical and mechanical
properties compared to coarse grain materials. Two methods have been
developed for UFG materials: “bottom-up” and “top-down”.