WE Colloquium: Michael Groeber, Combining characterization, modeling, and analytics towards understanding and manipulating process-structure linkages in metallic 3D printing
Additive manufacturing (AM) presents both extreme potential and concern for component design. In addition to the complicated geometries that AM enables, the ability to locally tailor processing path opens the door to sophisticated new designs with heterogeneous properties. However, accounting for this heterogeneity, before exploiting it, requires the ability to link local processing state to properties/performance of local material. A concern with current geometry-based design approaches, such as topology optimization, is not directly accounting for material property changes as geometry updates are made. Given current closed and fixed scanning strategies of most commercial systems, local processing paths are potentially altered significantly with seemingly minor macroscopic geometry changes and are unable to be avoided.
This talk will present methods for combining process monitoring, thermal modelling and microstructure characterization to mechanistically explain process-to-structure relationships in metal additive manufacturing. The talk will discuss heterogeneities in the local processing conditions within additively manufactured components and how they affect the resulting material structure. Methods for registering a fusing disparate data sources will be presented and the utility of different data sources for specific microstructural features of interest will be discussed. It is the intent that this talk will highlight the need for improved understanding of metallic additive manufacturing processes and show that combining experimental data with modelling and advanced data processing and analytics methods will accelerate that understanding, ultimately driving optimization routines for process control.
Additionally, this talk will outline building ICME modules that predict microstructure (grain size, texture, void Vf, etc.) from processing history and predict performance (E, σys, hardening rate, εf, etc.) from microstructure. These modules will be designed to interface with topology optimization codes to dynamically account for material properties as geometry updates are made. The work is being demonstrated using a laser-based powder-bed fusion process on nickel superalloy IN625 for thin-walled structures. Highly-pedigreed data sets of in-situ monitoring data (beam path, thermal measurements), post-build characterization (CT, RUS, 3D Optical and SEM) and mechanical testing (milli-tensile, HEDM, notch and torsion testing) will be collected and provided to the open community. Challenges problems will be commissioned to benchmark the current modeling capabilities in process-structure and structure-properties. Finally, challenge results will be used in novel forecasting techniques akin to weather forecasting strategies of model aggregation. This talk will present the current state of the program and the vision for community involvement.
Michael Groeber is currently a Senior Material Research Scientist in the Metals Branch of the Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio. Dr. Groeber’s research projects focus on the quantification and representation of microstructure for improving process and property modeling, in addition to structure and process optimization for additive manufacturing. Dr. Groeber is the originator/inventor and one of the principal developers of DREAM.3D, a unique software package that integrates several digital microstructure tools that will facilitate the advancement of Integrated Computational Material Science and Engineering (ICMSE) in the Air Force and outside. Additionally, Dr. Groeber has worked on creating autonomous, multi-modal data collection systems that integrate real-time analysis to optimize microstructure data collection and analysis. Recently, Dr. Groeber has focused on applying these developments to advancing the understanding of additive manufacturing. Dr. Groeber received a Bachelor's of Science degree in Materials Science and Engineering from the Ohio State University in 2003, followed by a Ph.D. from the Ohio State University in 2007. Dr. Groeber has published over 30 peer reviewed journals, 3 book chapters and presented over 20 invited international presentations.