Frontiers in Solidification: An MPMD Symposium Honoring Jonathan A. Dantzig: Additive Manufacturing
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS Functional Materials Division, TMS Light Metals Division, TMS Structural Materials Division, TMS: Aluminum Committee, TMS: Chemistry and Physics of Materials Committee, TMS: Process Technology and Modeling Committee, TMS: Solidification Committee
Program Organizers: Andre Phillion, McMaster University; Michel Rappaz, Ecole Polytechnique Fédérale De Lausanne; Melis Serefoglu, Marmara University; Damien Tourret, IMDEA Materials Institute
Wednesday 8:30 AM
March 22, 2023
Room: 28E
Location: SDCC
Session Chair: Charles-André Gandin, Mines ParisTech; Lindsay Greer, University of Cambridge
8:30 AM Invited
The Development of Grain Structure During Additive Manufacturing: A. Chadwick1; A. Birnbaum1; J.G. Santos Macias2; J. Steuben3; I. Athanasios3; J. Michopoulos3; G. Wagner1; M.V. Upadhyay2; Peter Voorhees1; 1Northwestern University; 2Ecole Polytechnique, Institut Polytechnique de Paris; 3Naval Research Laboratory
The morphology of grains produced during metal Additive Manufacturing (AM) can be very different from that given by conventional processing and is central to controlling the properties of the final build. To understand and control the unusual morphology of grains produced by additive manufacturing, a phase field model is developed that follows the evolution of many thousands of grains in three dimensions in the high velocity limit, which is easily accessible during AM, where the interface is planar or has low amplitude cells and as observed during AM of stainless steel 316L. A comparison between the predicted grain shapes and those measured experimentally using an AM machine and a novel laser-SEM device (developed by the Upadhyay group at Ecole Polytechnique) will be given. The comparison shows the importance of weld pool shape, heat flow, and anisotropy of the interfacial mobility in the observed grain morphologies.
9:00 AM Invited
Phase Field Study Rapid Solidification during Additive Manufacturing of SX Sample: Ingo Steinbach1; Murali Uddagiri1; 1Ruhr-University Bochum
During an additive manufacturing (AM) process, the component is subjected repeated thermal cycles which results in remelting of existing solidified structures. It is observed that during remelting of SX sample, there is predominant nucleation at the melt pool border for both as built and homogenized sample. In this work, we employ 3-D phase filed simulations to gain deeper understanding of nucleation mechanism during remelting of SX sample. The Multi Phase-Field model is coupled to both mass and heat transport phenomena including release of latent heat of solidification. The simulation studies are conducted for a quaternary model system of NiAlCrTa. A macroscopic CFD model is employed to obtain the heat fluxes at the boundaries (both the heat extraction rate and heat addition rate) which will act as accurate boundary conditions for microscopic PF simulation model.
9:30 AM
Development of a Multi-phase-field Framework for Powder Bed Fusion Additive Manufacturing: Tomohiro Takaki1; Shinji Sakane1; 1Kyoto Institute of Technology
Powder bed fusion (PBF) additive manufacturing can fabricate complex productions in a layer-by-layer manner. The process includes the melting and solidification of power particles by an electron beam. Therefore, highly accurate prediction of material microstructures and defects formed during the process is essential. In this study, we develop a numerical framework to predict microstructural evolutions formed during the PBF of a metallic alloy. Here, we couple the multi-phase-field models for solid phase sintering and polycrystalline solidification with liquid flow and solid motion to express power particles, melting of particles and substrate material, solidification, and liquid flow.
9:50 AM
Growth Competition between Columnar Dendritic Grains under Additive Manufacturing Conditions: Elaheh Dorari1; Kaihua Ji1; Adriana Castellanos2; Alec Saville2; Oliver Hesmondhalgh2; Joe McKeown3; Amy Clarke2; Alain Karma1; 1Northeastern University; 2Colorado School of Mines; 3Lawrence Livermore National Laboratory
A comprehensive understanding of the growth competition between columnar dendritic grains at high solidification rates is critically important for emerging technologies like additive manufacturing (AM). While this growth competition has been investigated extensively under conventional slow solidification conditions, it remains comparatively less explored at high growth rates. We present a combined experimental and computational study of microstructure and grain structure evolution in thin-films of Al-Si alloys solidified under AM conditions. This evolution is characterized using in situ Dynamic Transmission Electron Microscopy (DTEM) observation of solid-liquid interface dynamics together with post-mortem crystallographic mapping of columnar grain structures. The experimental results are interpreted using a new quantitative phase-field formulation of rapid binary alloy solidification that incorporates quantitively nonequilibrium effects at the solid-liquid interface. The experimental and phase-field simulations results are used to construct grain-boundary orientation selection maps, which highlight similarities and differences between grain selection mechanisms at slow and rapid solidification rates.
10:10 AM Break
10:30 AM Invited
Nucleation Burst in Additively Manufactured Inconel 718: Julien Zollinger1; Ivan Cazic1; Thomas Schenk1; Michael Engstler2; Benoît Appolaire1; 1Universite De Lorraine; 2Universität des Saarlandes
The fine equiaxed microstructure observed in additively manufactured Inconel 718 is shown to form through an icosahedral short-range order (ISRO) mediated nucleation mechanism. By coupling 3D EBSD and HRTEM observation, the key role of titanium carbides (TiC) is demonstrated. TiC, if present in remelted previous layer, lead to a local enrichment in niobium, leading to the nucleation of numerous metastable phases containing icosahedral clusters, and leading to the observed grain refinement. The influence of local thermal conditions, of the shape and positions of TiC are discussed to provide new insights into the grain refinement of nickel alloys processed by additive manufacturing.
11:00 AM Invited
Modelling and Validating Solidification Kinetics during Additive Manufacturing: Peter Lee1; Chu Lun Alex Leung1; 1University College London
Solidification kinetics and non-equilibrium phase formation in the semi-solid state governs the properties of components produced by a vast range of processes from thin slab cooling to additive manufacting. Many of the modelling techniques used to simulate these processes are based on the work done over the past 50 years by Jon Dantzig, ranging from the macroscopic, to microstructural to atomistic level. This talk will look at methods of validating models of the non-equilibrium solidification kinetics across the length scales during additive manufacturing. Where appropriate, correlations of the techniques used to those developed by Jon will be made, both in terms of simulation and experimental validation, ranging from his formulating dimensionless numbers to predict equilibrium vs non-equilibrium conditions to his reviews of the best flash x-ray diffraction techniques to use to capture transient phase changes.
11:30 AM Invited
Rationalization of the Modelling of Stress and Strain Evolution in Powder Bed Fusion Additive Manufacturing – A Perspective from a Background in the Simulation of Casting Processes: Steve Cockcroft1; 1University of British Columbia
There has been a tremendous body of work recently appearing in the literature focused on additive manufacturing including experimental based investigations, numerical investigations and combinations of the two. These studies generally focus on understanding and mitigating defect generation to improve product quality while minimizing cost. One defect of concern is residual component distortion and stress. In this paper, a coupled thermo-mechanical Finite Element (FE) model was developed to examine the buildup of in-elastic strain in Ti6Al4V during solidification of the melt pool at the mesoscale. The major challenges in developing an accurate model are discussed with reference to the lessons learned in modelling thermal stress generation and in-elastic strain accumulation in casting processes. Key areas requiring careful consideration include the high temperature constitutive and thermal strain behaviour as the material transitions from liquid, through a semi-solid state to a fully solid material.