Experimental and numerical studies on fabrication of nanoparticle reinforced aluminum matrix composites by friction stir additive manufacturing

Abstract

Friction stir additive manufacturing (FSAM) is applied to fabricate nanoparticle reinforced aluminum matrix composites. Monte Carlo model and precipitate evolution model were combined with the moving heat source model to simulate the fabrication of the nanoparticle reinforced aluminum matrix composites. Moving heat source model, Monte Carlo model and precipitate evolution model is used for the simulation of temperature field, microstructure evolution and mechanical property, respectively. The comparison between numerical model and experiment shows the validities of the established models on the temperature rises, the grain sizes and the mechanical properties. In this work, the physical mechanism of performance enhancement of nanoparticle reinforced aluminum matrix fabricated by FSAM is studied by both experimental and numerical methods. Dispersion of Al2O3 nanoparticles leads to the increase of hardness and the decrease of average grain size in composite layers. The spontaneous re-stirring and reheating in the stirring zone can reduce the aggregation of nanoparticles, which is the key factor determining the mechanical properties. With the increase of nanoparticle size, average grain size is increased and hardness is decreased. The increase of volume fraction of nanoparticles leads to finer grains and higher hardness.

Keywords

• Friction stir additive manufacturing
• Additive manufacturing
• Nanoparticle
• Composite