Effect of heat treatment on microstructure evolution of Inconel 718 alloy fabricated by selective laser melting
By Xing Li, J. Shi, Chenyang Wang, G. Cao, A. M. Russell, Z. Zhou, C. Li, G. Chen. Journal of Alloys and Compounds, 2018
229 citations recorded by the source corpus.
Abstract Inconel 718 superalloy was fabricated by selective laser melting (SLM) and subsequently subjected to different heat treatments. Microstructure evolution was examined by X-ray diffraction, optical microscopy, scanning and transmission electron microscopies. In the horizontal section (normal to the building direction) of the as-built sample, columnar and cellular sub-structures formed in the overlapping area, while only cellular sub-structures existed in the central fusion area. Columnar structures were observed in the vertical section (parallel to the building direction). In the as-built condition, austenite γ and Laves phases predominated, almost to the exclusion of all other phases. When treated by the direct double aging (DA) process, δ-Ni3Nb phases precipitated mainly in the interdendritic regions where Nb preferentially segregated. Homogenization plus double aging (HA), and solution plus double aging (SA) treatments significantly eliminated microsegregation and Laves phases owing to the diffusion of Nb and Ti to the γ matrix. The δ phase dissolved in the HA-treated sample but precipitated in the SA-treated sample. The γ′-Ni3(Al,Ti) phase was prone to precipitate when treated by HA, while γ″-Ni3Nb phase tended to precipitate in the SA sample. Due to the precipitation of the higher fraction of the major strengthening γ″ phases, the SA sample showed the highest hardness value among the as-built, DA, HA, and SA samples. The morphology, distribution and crystallography of precipitates and their formation mechanisms are discussed and analyzed.
Subfields: Mechanical Engineering
View Paper: https://www.semanticscholar.org/paper/ccdf4ccb6554f1720468aa9acbd1277e8bad70ac
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In Mechanical Engineering
Citations in the corpus
- Knowledge of process-structure-property relationships to engineer better heat treatments for laser powder bed fusion additive manufactured Inconel 718 (2019, background): “These observations give direct evidence for the as-printed Ti and Nb segregation they hypothesized in observing solution-annealed AM-IN718 microstructures, and is consistent with previous reporting [17,21,57,68].”