Three-dimensional grain growth during multi-layer printing of a nickel-based alloy Inconel 718
By H. Wei, Gerald L. Knapp, T. Mukherjee, T. DebRoy. Additive Manufacturing, 2019
136 citations recorded by the source corpus.
Abstract Heterogeneous grain structure is a source of the inhomogeneity in structure and properties of the metallic components made by multi-layer additive manufacturing (AM). During AM, repeated heating and cooling during multi-layer deposition, local temperature gradient and solidification growth rate, deposit geometry, and molten pool shape and size govern the evolution of the grain structure. Here the effects of these causative factors on the heterogeneous grain growth during multi-layer laser deposition of Inconel 718 are examined by a Monte Carlo method based grain growth model. It is found that epitaxial columnar grain growth occurs from the substrate or previously deposited layer to the curved top surface of the deposit. The growth direction of these columnar grains is controlled by the molten pool shape and size. The grains in the previously deposited layers continue to grow because of the repeated heating and cooling during the deposition of the successive layers. Average longitudinal grain area decreases by approximately 80% when moving from the center to the edge of the deposit due to variable growth directions dependent on the local curvatures of the moving molten pool. The average horizontal grain area increases with the distance from the substrate, with a 20% increase in the horizontal grain area in a short distance from the third to the eighth layer, due to competitive solid-state grain growth causes increased grain size in previous layers.
Subfields: Automotive Engineering, Mechanical Engineering
View Paper: https://www.semanticscholar.org/paper/1a330f7dd86dd2cc2d9359923d3837a9cfd48eef
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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): “In this work, sufficient understanding of the process-structure-property relationships of L-PBF AM Inconel 718 (IN718) subjected to post-processing heat treatments is established to enable purposeful design of better heat treatments for AM-IN718 materials.”