Microstructures and strengthening mechanisms of Cu/Ni/W nanolayered composites

Abstract

Cu/Ni/W nanolayered composites with individual layer thickness ranging from 5 nm to 300 nm were prepared by a magnetron sputtering system. Microstructures and strength of the nanolayered composites were investigated by using the nanoindentation method combined with theoretical analysis. Microstructure characterization revealed that the Cu/Ni/W composite consists of a typical Cu/Ni coherent interface and Cu/W and Ni/W incoherent interfaces. Cu/Ni/W composites have an ultrahigh strength and a large strengthening ability compared with bi-constituent Cu–X (X = Ni, W, Au, Ag, Cr, Nb, etc.) nanolayered composites. Summarizing the present results and those reported in the literature, we systematically analyze the origin of the ultrahigh strength and its length scale dependence by taking into account the constituent layer properties, layer scales and heterogeneous layer/layer interface characteristics, including lattice and modulus mismatch as well as interface structure.

Keywords:

• metallic nanolayered composite
• strength
• length scale
• interface
• dislocation

Acknowledgments

This work was supported by the National Natural Science Foundation of China (Grant Nos. 50890173 and 50971125), the National Basic Research Program of China Grant No. 2010CB631003), and the China-Australia Special Fund for Science & Technology Cooperation (Grant No. 50811120106).