Unraveling the extraordinary strengthening effect of TiC nanoparticles in Al matrix composites fabricated via laser powder bed fusion

Ductility collapse is an obstacle to achieve superior strengthening effect while developing high-strength Al matrix composites. In this study, we demonstrate that as much as 8 wt% of TiC nanoparticles could be incorporated into Al matrix during laser powder bed fusion (LPBF), which exert an extraordinary strengthening effect of 222% with an acceptable elongation of 17%. Microstructural analysis shows that majority of those TiC nanoparticles survive from the LPBF process and distribute uniformly at both Al grain boundaries and within Al grains interior. With 8 wt% of TiC nanoparticles, the average grain size could be refined from 28.4 μm to 1.66 μm, corresponding to 94% grain refinement effect. The combined effect of the uniformly distributed high-density dispersoids and the significant grain refinement results in the extraordinary strengthening effect of TiC nanoparticles. This study may provide some guidance for the development of high-performance Al matrix composites via LPBF.