The Project from National Natural Science Foundation of China，No.11272072，2013.1-2016.12
Study on dynamic mechanical behavior and strengthening-toughening mechanisms of magnesium alloy based nanocomposites is the new development trends of the deeper research and utilization of lightweight alloys. This project is carried out by the experiment and numerical analysis. In the experiment, the macroscopic-microscopic tensile behaviors and the effects of temperature and strain rate on the tensile constitutive relation of the magnesium alloy based nanocomposites with different hybrid ratios are investigated. The constitutive equation and mechanical property parameters of the heterogeneous nanocomposites are determined. In theory and numerical simulation, the effects of different fractal box dimensions, hybrid ratios of nanosized hybrid reinforcements, and the interfacial bond strength of the reinforcements and matrix on the mechanical properties of the hybrid composites are numerically researched according to the fractal and homogenization theory as well as digital image processing technology. Finally, the validity of all kinds of microstructure models will be analyzed and a novel theoretical strengthening-toughening model for nanosized hybrid reinforcements will be established by combining with the results of experiments. The present study is of great theoretic and innovating significance to enrich the theories for metal matrix nanocomposites and to expand the application fields of the lightweight alloys.