|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Microstructural Templates Consisting of Isostructural Ordered Precipitate / Disordered Matrix Combinations: Microstructural Evolution and Properties
||On the Detailed Morphological and Chemical Evolution of Phases during Laser Powder Bed Fusion and Common Post-processing Heat Treatments of IN718
||Sophie Primig, Vitor Rielli, Alessandro Piglione, Minh-Son Pham
|On-Site Speaker (Planned)
Recently, IN718 has shown great viability for laser powder bed fusion (LPBF) additive manufacturing of aerospace parts. However, the detailed microstructure-property relationships during thermal profiles typical to LPBF are not yet well understood.
Using atom probe microscopy, we report on the detailed morphological and chemical evolution of phases in IN718 after LPBF with chessboard versus meander scanning strategies, and common ageing treatments. Due to differences in scanning vector length, coarser dendritic structures, Laves particles and Al clusters are found in the chessboard strategy. Coarser matrix grains and a higher dislocation density are detected in the meander strategy. The formation of σ phase at grain boundaries, a nucleation site for MC carbides, must be considered for selection of post-processing treatments. Retained Laves phase after direct ageing causes lower fractions of nanoscale γ" precipitates. A quadruple fraction of stable, larger γ" precipitates is found after homogenization and ageing, causing partial matrix recrystallization.