Journal
COMPOSITES PART B-ENGINEERING
Volume 239, Issue -, Pages -Publisher
ELSEVIER SCI LTD
DOI: 10.1016/j.compositesb.2022.109994
Keywords
Selective laser melting; Inconel 718; Laves phase; Formation mechanism; Dissolution behavior
Funding
- National Key Research and Development Program of China [2018YFB1105800, 2018YFB1105900]
Ask authors/readers for more resources
This study explains the unexpected increase of Laves phase in Inconel 718 manufactured by selective laser melting (SLM) and clarifies its distinct dissolution behavior during heat treatment through a comparative analysis. SLM-built IN718 has a higher cooling rate, resulting in more trapped Nb atoms in the matrix and fewer inter-dendritic Laves phases. The dissolution of Laves phase during homogenization treatment is controlled by three-dimensional diffusion and interface reaction processes.
In this study, we explain why the amount of Laves phase in Inconel 718(IN718) manufactured by selective laser melting (SLM) unexpectedly increases under extremely rapid solidification and clarify its distinct dissolution behavior during heat treatment based on a comparative analysis of laser directed energy deposition (L-DED)-built and cast IN718. Compared with the cast and L-DED, SLM has much higher cooling rate, which greatly improves the dendrite growth rate and the solute trapping during the solidification process of molten pool. Thus, more Nb atoms are trapped in the matrix, and less Nb atoms are expelled to form inter-dendritic Laves phase in SLM-built IN718. However, the volume fraction of Laves phase is the highest in SLM-built IN718, which is attributed to the lower Nb concentration in the Laves phase and few Nb-rich region. During homogenization treatment, the dissolution of Laves phase is controlled by three-dimensional diffusion process at the early stage, and then is mainly controlled by the interface reaction process. After homogenization, there are still many tiny carbides, oxides, and nitrides undissolved both along the grain boundaries and inside the grains.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available