Synthesis And Tensile Properties Of Bulk Nanocrystalline Cu By Electrical Brush-plating Technique At Room Temperature

The tensile properties of nanocrystalline (nc) metals have been a main research topic in materials science communities, which involve quantificational descriptions of macro-mechanical behavior and qualitative analyses of micro-deformation mechanisms of nc metals. However, due to synthesis problems, bulk nc metals with high metallurgical qualities and truly nc structures cannot be prepared so far. This leads to considerable limits to substantial understanding of plastic deformation mechanisms of nc metals. On the other hands, it has been suggested that grain boundary (GB) process and dislocation activities are the two main mechanisms controlling mechanical properties of nc metals. It is a center problem of plastic deformation mechanism investigations to reveal the effects of both mechanical and thermal roles caused due to changes in grain size, temperature and stain rate.Based on the above two points, the following research work was conducted in this doctoral dissertation and the resultant conclusions are presented as the following:1. A new electrical brush-plating technique for synthesizing bulk nc-Cu with high metallurgical qualities and truly nc structure was developed. The stylus is made by a stainless steel (AISI304) wrapped by cotton and polypropylene fabric, the bath contents CuSO4·5H2O, NH4NO3, C6H8O7·H2O and a small amount of additives. During the...