The strengthening effect of carbon nanotube in metal matrix composites considering interphase

• The roles of the interphase and load transfer effect are analyzed.
• The plastic behavior of interphase is addressed by amorphous plasticity model.
• A three-phase composite model is proposed to investigate the coupled effect.
• The effects of matrix grain size, content and size of CNT are also presented.

The formation of interphase around carbon nanotube (CNT) has been observed experimentally in metal matrix composites (MMCs). However, the characterization of mechanical behavior of interphase and its contribution to the elastoplastic response of MMCs are still open issues. In this paper, a theoretical model is developed to describe the coupled impact of interphase and load transfer effect induced by the reinforcement on the overall mechanical behavior of CNT-reinforced MMCs. The plastic property of interphase is addressed by the rate-dependent amorphous plasticity model. The effective elastic modulus of MMCs is considered to be sensitive to the content of interphase, and the introduction of interphase can obviously enhance the overall strength of the composites. In addition, the effects of matrix grain size, the content and size of the reinforcement have also been addressed in details. The comparisons between the predictions and available experimental data have been performed to validate the applicability of the proposed scheme.