On the primary spacing and microsegregation of cellular dendrites in laser deposited Ni-Nb alloys

Abstract

In this study, an alloy phase-field model is used to simulate solidification microstructures at different locations within a solidified molten pool. The temperature gradient $G$ and the solidification velocity $V$ are obtained from a macroscopic heat transfer finite element simulation and provided as input to the phase-field model. The effects of laser beam speed and the location within the melt pool on the primary arm spacing and on the extent of Nb partitioning at the cell tips are investigated. Simulated steady-state primary spacings are compared with power law and geometrical models. Cell tip compositions are compared to a dendrite growth model. The extent of non-equilibrium interface partitioning of the phase-field model is investigated. Although the phase-field model has an anti-trapping solute flux term meant to maintain local interface equilibrium, we have found that during simulations it was insufficient at maintaining equilibrium. This is due to the fact that the additive manufacturing solidification conditions fall well outside the allowed limits of this flux term.

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Cited by in corpus (13)

• Application of Finite Element, Phase-field, and CALPHAD-based Methods to Additive Manufacturing of Ni-based Superalloys
• Finite Interface Dissipation Phase Field Modeling of Ni-Nb under Additive Manufacturing Conditions
• Single-Track Melt-Pool Measurements and Microstructures in Inconel 625
• Simulation and analysis of $\gamma$-Ni cellular growth during laser powder deposition of Ni-based superalloys
• Predictive modeling of solidification during laser additive manufacturing of nickel superalloys: Recent developments, future directions
• Formation of Nb-rich droplets in laser deposited Ni-matrix microstructures
• Uncertainty Analysis of Microsegregation during Laser Powder Bed Fusion
• Simulation of temperature, stress and microstructure fields during laser deposition of Ti-6Al-4V
• Microstructural and Mechanistic Insights into the Tension-Compression Asymmetry of Rapidly Solidified Fe-Cr Alloys: A Phase Field and Strain Gradient Plasticity Study
• Tusas: A fully implicit parallel approach for coupled phase-field equations
• Orientation selection in alloy dendritic evolution during melt-pool solidification
• Phase-Field Study of Polycrystalline Growth and Texture Selection During Melt Pool Solidification
• Effects of isotherm patterns on cellular interface morphologies of melt pool origin