Proceedings of the
9th International Conference of Asian Society for Precision Engineering and Nanotechnology (ASPEN2022)
15 – 18 November 2022, Singapore

Influence of TiC Reinforcement Particles on the Mechanical Properties and Microstructures of Heat-Treated IN718 Composite

Duy Nghia Luu1, Sharon Mui Ling Nai1,a and Wei Zhou2

1Singapore Institute of Manufacturing Technology, Agency for Science, Technology and Research (A*STAR), 73 Nanyang Drive, Singapore 637662, Singapore

2School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore


In this study, TiC reinforcement particles were used to fabricate IN718/TiC composite using selective laser melting technology. The interactions between the reinforcement particles and the IN718 matrix during the solutionizing and aging processes were investigated. It was found that the addition of TiC particles contributed to the reduction of solute segregation at the grain boundary and the susceptibility to hot cracking. The results indicated that the solute materials (Nb and Mo) were absorbed by TiC particles through Ostwald ripening mechanism instead of diffusing to the grain boundaries. In addition, noticeable improvements in strength and microhardness were observed after heat treatment in comparison with the as-printed sample. It was shown that the addition of TiC particles also facilitated the formation of nano-sized carbonitride precipitates in the as-printed sample. These precipitates could still be observed after the heat treatment process and contributed significantly to the grain refinement and strengthening of the heat-treated samples. Moreover, the combination of finer grains and segregation mitigation resulted in γ' and γ'' precipitates being distributed more homogeneously. This study has demonstrated the significant benefits of TiC particles in further improving the mechanical performance of selective laser melted IN718.

Keywords: Selective laser melting, Additive manufacturing, Inconel 718, TiC, Mechanical properties, Microstructures.

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