Electron theory based explanation and experimental study on deformation behavior of Cu/Ni multilayers

• DOI: 10.1007/bf03185982
• Publication Date: 2010-04-23T13:52:07Z
• Authors: F. Z. Ren; P. Liu; M. Zheng; Q. M. Dong; G. S. Zhou; Q. Yuan
• Keywords: 02 engineering and technology; 0210 nano-technology

Cu/Ni multilayers with various defined thickness of Cu and Ni layers were electrodeposited on low carbon steel substrates. Hardness measurements indicated that the increase in yield strength (one-third of hardness) with a decrease of layer thickness for Cu/Ni multilayers with single layer thickness at sub-micron length scale could be described by the Hall-Petch formula of the dislocation pile-up model. In the regime of few tens to a hundred nanometers of single layer thickness, the dislocation pileup-based Hall-Petch model broke down. This could be explained quantitatively according to the criterion condition on the limit size of dislocation derived from a modified Thomas-Fermi-Dirac electron theory.