Book Description
Nanocrystalline (nc) materials are characterized by a grain size in the range 1-200 nm. Because of this characteristic, these materials exhibit unique microstructures in which the volume of grain boundaries is significant. Nc-materials offer interesting possibilities related to many structural applications. In order to explore some of these possibilities, an understanding of the origin of mechanical properties such as strength, hardness, and ductility is essential. Mechanical properties in materials are very sensitive to their microstructure. One important process that can be used to manipulate the details microstructure in materials is annealing. In the present dissertation, annealing treatment was utilized to provide insight into the correlation between mechanical properties and microstructure. Primary among the mechanical properties that were selected for investigation are hardness, the elastic modulus, strength and ductility. Experiments on hardness and the modulus of elasticity were conducted at room temperature on samples of electrodeposited (ED) nc-Ni that were annealed at temperatures ranging from 323 K to 693 K. The results showed the presence of three regions: regions I, II, and III. In region I (300 K T 350 K), hardness and the elastic modulus remained essentially constant. In region II (350