Computational Techniques for Multi-Scale Modeling in Advanced Manufacturing: Modeling of Microstructural Evolution
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS Extraction and Processing Division, TMS: Computational Materials Science and Engineering Committee, TMS: Process Technology and Modeling Committee
Program Organizers: Adrian Sabau, Oak Ridge National Laboratory; Anthony Rollett, Carnegie Mellon University; Laurentiu Nastac, University of Alabama; Mei Li, Ford Motor Company; Alexandra Anderson, Gopher Resource; Srujan Rokkam, Advanced Cooling Technologies, Inc.
Wednesday 2:00 PM
March 17, 2021
Room: RM 1
Location: TMS2021 Virtual
Session Chair: Laurentiu Nastac, The University of Alabama
2:00 PM Invited
In Situ and Operando Synchrotron Experiments for Additive Manufacturing Model Validation: Peter Lee1; Chu Lun Alex Leung1; Yunhui Chen1; Samuel Clark1; Sebastian Marussi1; Robert Atwood2; Martyn Jones3; Gavin Baxter3; 1University College London; 2Diamond Light Source; 3Rolls-Royce plc
Additive Manufacturing (AM), both Laser Powder bed Fusion (LPBF) and Laser Blown Powder Directed Energy Deposition (LBP-DED) promise to produce and repair unique, high quality components from aerospace to biomedical applications. However, the underlying physics controlling the melting, solidification, flow and other phenomena are still poorly understood. Many groups are modelling these processes, but more work experimental investigations are required to estimate many of the initial, boundary and material properties. Here, we present two unique in situ and operando LPBF and LBP-DED rigs that correlatively image the process using synchrotron X-ray, optical and infra-red imaging to capture the underly phenomena that control AM. We show how correlative imaging can be used to both inform and validate analytic and computational models of the process for a wide range of materials from bio-ceramics to Ni superalloys to Ti alloys.
2:40 PM
Investigation of Powder Spattering in Laser Powder Bed Fusion through Multi-physics Modeling and High-speed Synchrotron X-ray Imaging: Xuxiao Li1; Qilin Guo2; Zachary Young3; Fangzhou Li1; Lianyi Chen2; Wenda Tan1; 1University of Utah; 2University of Wisconsin-Madison; 3Missouri University of Science and Technology
In the laser powder fusion process, the powder spattering contributes to the formation of defects such as lack-of-fusion and surface irregularity. The powder-gas interaction that triggers such spattering can be inferred from experimental observations but has not been well quantified. In this work, we use a synergistic experimental/numerical approach to investigate the powder-gas interaction and the resultant powder spattering behavior. On the experimental side, the synchrotron X-ray imaging is used to observe the powder spattering in the cases with different laser power, laser scanning speed, and ambient pressure. On the modeling side, a three-dimensional multiphysics model that captures the multi-phase thermofluidic dynamics and powder dynamics will be used to quantitatively predict the force(s) of gas-powder interaction in different cases. The combination of the experimental and numerical results will provide a comprehensive understanding of the physical mechanisms of powder spattering in the process.
3:05 PM
Particle Resolved Simulation of Laser Powder-bed Fusion Including Metal Evaporation and Vapor Plume Dynamics: Juergen Jakumeit1; Romuald Laqua1; Gongyuan Zheng1; Yuze Huang2; Samuel Clark2; Peter Lee2; 1Access E.V.; 2University College London
Laser Powder-Bed Fusion (LPBF) of metal alloys is the most widely used Additive Manufacturing (AM) process for metals. However, our ability to use computational simulations of the process for optimization is still limited, as is our understanding of some of the underlying mechanisms. Here we develop a multi-phase melting, evaporation and solidification computational simulation, which treats melt vapor as ideal gas. We study in detail the formation of keyhole in the melt-pool, the metal vapor plume dynamics and the impact on defect formation. The simulation results are validated with transient melt-pool and keyhole dimensions measured from in situ synchrotron X-ray imaging during LPBF. We determine the influence of process parameters on the strength and formation of the metal vapor plume. The results of our study increase our understanding of the multi-phase nature of LBPF including spatter and the formation and content of pores.
3:30 PM
Phase-field Modeling of The Evolution Kinetics of Porous Structure During Dealloying of Binary Alloys: jie li1; 1The Hong Kong Polytechnic University
A multi-phase-field model is proposed to investigate the porous structure evolution during electrochemical dealloying of binary alloys. The Allen-Cahn equations and modified Cahn-Hillard equations are established to govern phase transformation, bulk and surface diffusion, and chemical reactions. It is found that a thermal noise term disturbed the initial stability of the dealloying front by the heterogeneous nucleation of the porous phase. The growth of porous clusters further exposes the interior inert element to the electrolyte, leading to a constant dealloying velocity of porous structural growth. By investigating the effect of dealloying temperature, chemical content of the electrolyte, and precursor alloy composition, we demonstrate the complex pattern evolution of porous structure from the competition between the corrosion-induced surface roughening and diffusion-induced surface smoothing. The characteristics of porous structural evolution, such as dealloying velocity, ligament size, and residual inert element content under different dealloying conditions, are in good agreement with experimental observations.
3:55 PM
Fluid Dynamics Effects on Microstructure Prediction in Single-Laser Tracks for Additive Manufacturing: Adrian Sabau1; Lang Yuan2; Narendran Raghavan1; Matthew Bement1; John Turner1; 1Oak Ridge National Laboratory; 2University of South Carolina
The Laser Powder Bed Fusion Additive Manufacturing (LPBFAM) is one of the most important processes for the production of complex, high-performance end-use metal parts. Single-tracks laser fusion were simulated using a heat-transfer-solidification-only (HTS) model and its extension with fluid dynamics (HTS_FD) model using Truchas, a Los Alamos National Laboratory parallel open-source code, which included laminar fluid dynamics, flat-free surface, heat transfer, phase-change, evaporation, and surface tension phenomena. Correlation-based models for primary dendrite arm spacing (PDAS) using thermal gradient (G) and solidification velocity(V) were evaluated using the data on G and V from both HTS and HTS_FD simulations in order to quantify the effect of the fluid dynamics on the microstructure. Simulation results for PDAS indicate that fluid dynamics affects the solidification microstructure and yields more accurate results for PDAS. A new PDAS correlation, based on (G, V) results from the HTS_FD model was developed and validated against experimental results.