Effect of Carbide Inoculants Additions in IN718 Fabricated by Selective Laser Melting Process

This article presents the effect of carbide inoculants additions on microstructure evolution and mechanical properties of Inconel 718 superalloy fabricated by selective laser melting (SLM) process. Flakes of titanium carbide (TiC) and niobium carbide (NbC) were mixed with the Inconel 718 powder and acted as nucleating agents to induce heterogenous nucleation in order to eliminate anisotropic grain structure. By increasing fraction of carbide inoculants, more isotropic grain texture was detected. Furthermore, significant improvements on creep properties have been observed with minor carbide additions. With 0.5 wt% TiC and NbC addition, creep rupture life could be increased from 198.5 h to 449.5 h and 371.8 h, respectively. Moreover, creep strain rate was dramatically decreased from 0.513 × 10−8 to 0.12 × 10−8 s−1 by 0.5 wt% TiC additions. This study has demonstrated that minor carbide addition can have profound impact on the microstructure and property of Inconel718 processed by SLM.