In-situ blended 316L-Si and PH48S via laser directed energy deposition for functionally graded applications

Laser powder blown directed-energy deposition (DED) enables the flexible fabrication of functionally gradient structures. In the region where multiple feedstocks are blended, it is natural to apply the ‘rule of mixtures’. Here, we show that by blending PH48S and 316L-Si steel powders using DED, the resulting material possesses lower yield strength but increased hardening and a secondary hardening regime not observed in the original alloys, invalidating direct interpolation between feedstock properties. Microstructural analysis of the mixed material revealed a solidification-driven multi-phase hierarchal microstructure. This result enables greater accuracy and increased design space in the co-design of materials and manufacturing processes.