Mechanical Alloying

Mechanical alloying is defined as high-energy ball milling, whereby due to the powder-ball impacts (left figure) cold welding and fracturing of powder particles are repeated, which leads to true alloying of elementary powder (formation of metastable phase or solid solution) or to fine distribution of particle in matrix (ODS alloys). The intensity of cold welding and fracturing of powder, respectively the finla microstructure, is depending on the plastic properties of the elementary powder. In dependence on this there are in principle three systems:

1. ductil-ductil: Cu-Nb, Cu-Ag (lamelare microstructure, solid solution (right)
2. ductil-brittle: Cu-Y2O3, Cu-Mo (distribution of fine particle in matrix)
3. brittle-brittle: Ge-Si (metastable phase, amorphisation)