Grain refinement of additively manufactured commercial purity aluminum by addition of TiC heterogeneous nucleation site particles

In this study, effects of heterogeneous nucleation site particles on density, microstructure and hardness were studied in the pure aluminum samples additively manufactured by laser-based powder bed fusion (PBF-LB) method with a small amount of TiC particles. It was found that higher density of the sample was found by addition of small amount of TiC particles. It was also found that the sample containing 1.0 vol% TiC particles has the most refined microstructure. In addition, the samples fabricated with 0 vol% and 0.1 vol% TiC particles have <101> texture along building direction, whereas <100> texture was observed for the samples with 0.5 vol% and 1.0 vol% TiC particles. As the volume fraction of TiC particles increases, the hardness of the samples was also increased. Higher hardness in the samples with TiC particles was mainly caused by not reinforcement effects of TiC particles but refinement of grain structure by heterogeneous nucleation. © 2022 The Japan Institute of Light Metals