Additive Manufacturing Benchmarks 2022 (AM-Bench 2022): Materials III: Dendrite Scale
Program Organizers: Brandon Lane, National Institute of Standards and Technology; Lyle Levine, National Institute of Standards and Technology
Tuesday 1:30 PM
August 16, 2022
Room: Regency Ballroom III & IV
Location: Hyatt Regency Bethesda
Session Chair: David Rowenhorst, Naval Research Laboratory
1:30 PM Invited
Simulating Spot Melts in 3D with Dendrite-scale Resolution
: Stephen DeWitt1; Christopher Newman2; Stephen Nichols1; Jean-Luc Fattebert1; Balasubramaniam Radhakrishnan1; James Belak3; John Turner1; 1Oak Ridge National Laboratory; 2Los Alamos National Laboratory; 3Lawrence Livermore National Laboratory
High fidelity additive manufacturing simulations at the melt-pool scale have been demonstrated in recent years as part of the AM-Bench Challenge and elsewhere. When these simulations include microstructure evolution, it is usually limited to grain envelopes (e.g. using cellular automata methods) due to computational constraints. Here we show that advancements in hardware and software make higher resolution simulations possible, using the Tusas phase-field code that can efficiently use the entire 200 petaFLOP/s Summit supercomputer. We present a 3D phase-field simulation of the solidification of an entire spot melt in a single crystal binary alloy that resolves dendritic/cellular features. This approach allows us to investigate the non-steady-state evolution of the sub-grain solidification morphology and the associated solute microsegregation as the solidification front traverses rapidly changing thermal conditions across the melt pool. We also discuss planned extensions to polycrystalline systems.
2:00 PM Invited
Prediction of Large Domain Microstructure Morphology by a Novel 3-Dimensional Cellular Automata-phase Field Modeling Approach: Shunyu Liu1; Yung Shin2; 1Clemson University; 2Purdue University
This talk presents a novel hybrid approach, called the Cellular Automata-Phase Field model, which can accurately predict the dendrite formation in a large domain, which combines a 2D/3D CA model with a 1D PF component. In this integrated model, the PF component is employed to accurately calculate the local growth kinetics including the growth velocity and solute partition at the solidification front while the 3D CA component uses the growth kinetics as inputs to update the dendritic morphology variation and composition redistribution throughout the entire domain. The CAPF approach can improve the computational efficiency by 5 orders of magnitude over the PF approach. Using this approach, the prediction of microstructure morphology in a large domain is demonstrated based on the temperature field calculated by the accurate thermal model of additive manufacturing. Case study examples are shown for directed energy deposition of Ti6Al4V alloy and laser welding of SS304.
2:30 PM
(On-Demand) Modelling of Chemical Species Mixing During In-situ Alloying of Ternary Alloys and Effect on Rapid Grain Growth: Junji Shinjo1; Chinnapat Panwisawas2; 1Shimane University; 2University of Leicester
In-situ alloying using laser-based additive manufacturing is simulated for the ternary Ti-Zr-Cu system to elucidate thermal-chemical-fluid flow dynamics and species mixing characteristics, which is significant in designing alloys used for biomedical applications. In the configuration of powder-bed fusion, process parameters such as laser power and laser scanning speed are investigated, which affect the melt pool size and induced flow velocity where chemical species mixing is determined. In this ternary alloy system, the cooling behaviour is examined and discussed, which is significantly important to determine crystallisation or formation of metallic glass. The high-fidelity modelling approach is extended to physics-based grain growth modelling during rapid solidification, including the effects of thermal gradient and chemical composition distribution.
2:50 PM Break