ICME 2023: App.: AM Microstructure II
Program Organizers: Charles Ward, AFRL/RXM; Heather Murdoch, U.S. Army Research Laboratory
Wednesday 1:20 PM
May 24, 2023
Room: Boca I-III
Location: Caribe Royale
Session Chair: Adam Kopper, Mercury Marine
1:20 PM
Automated Characterization of Generated Meltpool from High Speed Camera in Advanced Manufacturing: Kristen Hernandez1; John Lewandowski1; Roger French1; Laura Bruckman1; Jayvic Jimenez1; Thomas Ciardi1; Sameera Venkat1; 1CWRU
Metal-based additive manufacturing success requires active monitoring solution for assessing quality and reliability of components. Monitors such as high speed cameras are a common and well-studied capture device for in-situ welding. The scale and time required to fabricate parts increases exponentially the number of relevant frames for feature detection, with higher resolution increases the number of feature occurrences. Techniques for automated feature extraction and quantification are required in order to perform active sensing so that errors or problems in the print process can be addressed. Laser-solid interactions present in meltpools, such as the uniformity of melt, are known predictors of build quality. Automatically determining major, minor axis, melt coordinate center, and overall area offers the first steps of using in situ measurements in real-time and obtaining characterization information to inform on print quality with minimal human intervention through the use of U-Net feature extraction and YOLO image segmentation.
1:40 PM
3D Phase-field Modelling of Microstructure Evolution During Additive Manufacturing of Multi-component Single Crystal Ni-based Super Alloys: Murali Uddagiri1; Ingo Steinbach1; 1Ruhr University Bochum
Phase-field models offer the possibility of simulating microstructure evolution under rapid solidification conditions without having to neglect the key physical mechanisms such as nucleation, growth kinetics and solute diffusion. However, until now the phase-field simulations are mostly restricted to binary alloys owing to the complexity of obtaining thermodynamic descriptions for technical alloy compositions. In this study, we employ 3-Dimensional multi-component and multi-phase-field simulations directly coupled to thermodynamic database to obtain the bulk free energies of individual phases. In addition, thermal boundary conditions of AM are implemented in such a way that the solver allows to model both melting and solidification (with latent heat release) simultaneously. The phase filed equations are implemented in openphase studio, a C++ based software package offered by OpenPhase Solutions. Through the 3-D simulations, microstructure evolution especially the dendrite morphology, primary dendrite arm spacing and solute segregation of full alloy composition of CMSX4 is studied in detail.
2:00 PM
Predicting Grain Morphology in LBPF Haynes 282 with Complex Geometry via ICME Approach: Yu-Tsen Yi1; Junwon Seo1; Anthony Rollett1; 1Carnegie Mellon University
Quantifying the grain size and orientation is essential for understanding the properties of the materials, especially when increasing the creep resistance of high-temperature alloys such as Haynes 282. The grain distribution of additively manufactured metal is attributed to various factors, such as processing parameters and part geometry, making it difficult to predict the microstructure. Haynes 282 being an FCC single-phase structure, polarized light methods cannot be applied to segment out grains accurately. Therefore, it is challenging for other imaging methods to segment and analyze the orientation of the grains. In this work, we present a cost-and-time-efficient pipeline for predicting grain size and orientation distributions. This method uses a convolutional neural network (CNN) that segments out grains in SEM images and predicts a relative grain orientation, which can work as an alternative for time-consuming EBSD.
2:20 PM
Columnar to Equiaxed Transition During Solidification Under Additive Manufacturing Conditions: Bala Radhakrishnan1; Tahany El-Wardany2; Ranadip Acharya3; 1Oak Ridge National Laboratory; 2Raytheon Technologies Research Center; 3Collins Aerospace
We present phase field (PF) simulations of the columnar to equiaxed transition (CET) occurring during solidification of Ti-Cu and Ni-Fe-Nb alloys under thermal conditions characteristic of powder fusion based additive manufacturing techniques. The PF simulations will involve direct coupling to alloy thermodynamics and a thermodynamically consistent nucleation model. The simulations are able to capture the transition from a solute-diffusion driven constitutional undercooling to thermal undercooling driven nucleation ahead of the epitaxial solidification front under AM conditions. A parametric study is presented under varying G and R conditions and alloy composition to capture the conditions under which the above transition occurs. This research was performed at the Oak Ridge National Laboratory under contract DE-AC05-00OR22725 with the United States Department of Energy (USDOE) and was supported by the High-Performance Computing for Manufacturing (HPC4Mfg) and the Exascale Computing Project (ECP) programs sponsored by the USDOE.
2:40 PM
Composition-microstructure Control of in-situ Alloying Using Laser Powder-bed Fusion Additive Manufacturing: High-fidelity Thermal-chemical-fluid-microstructure Modelling: Junji Shinjo1; Chinnapat Panwisawas2; 1Shimane University; 2Queen Mary University of London
Nucleation and grain growth during metal additive manufacturing (AM) remain debatable since the nature of rapid melting and solidification induced by laser-powder interaction during AM may cause heterogeneous mixing liquid metal behaviour especially when in-situ alloying is used. Coupled thermal-chemical-fluid-microstructure modelling is developed for simulating in-situ AM to understand the chemistry-induced solidification, re-melting and microstructure development. The results indicate that thermal fluid flow and chemical mixing play an important role in rapidly solidified microstructure. The heterogeneous nucleation resulting from undercooling due to large thermal gradient and large cooling rate initiates grain nuclei forming equiaxed grains, and with the extent of thermal gradient, more anisotropic columnar grain growth occurs in AM. The keyhole serves as a strong stirrer to enhance chemical species mixing by inducing convective flow motion, which determines the local chemical composition and microstructure in in-situ alloying while melting newly fed powders and re-melting part of the previous layer.
3:00 PM Break