Laser powder bed fusion of nano-CaB6 decorated 2024 aluminum alloy

The 2024 aluminum alloy (Al-Cu-Mg) is widely used in aerospace; however, due to its solidification-cracking tendency, processability using laser powder bed fusion (LPBF) remains a critical issue. addition of 2 wt% CaB6 nanoparticles induces columnar-to-equiaxed transition (CET), resulting an immediate improvement LPBF processability. High-density (>99.5%) and crack-free specimens, with homogeneous equiaxed microstructure without preferred grain orientation, were obtained. small average α-Al size 0.91 ± 0.32 µm attributed the similar lattice constants Al facilitating nucleation on nanoparticles, highly coherent Al/CaB6 interface. act as heterogeneous nucleus exert pinning force boundaries, which reduces coarsening. as-built specimens exhibit both high-yield strength (348 16 MPa) high-tensile (391 22 MPa), combined high total elongation at break (12.6 0.6%). macro hardness amounts 132 4 HV5.