Additive Manufacturing Keynote Session: Additive Manufacturing Keynote Session
Program Organizers: Allison Beese, Pennsylvania State University

Monday 2:00 PM
February 28, 2022
Room: 257
Location: Anaheim Convention Center

2:00 PM Introductory Comments

2:05 PM  Keynote
Metallic Alloy Microstructure Control under Additive Manufacturing Conditions: Amy Clarke1; 1Colorado School of Mines
    Large temperature gradients, high solidification velocities, and repeated cycles of heating and cooling are typically experienced during additive manufacturing (AM). Combinations of thermal gradient and solid/liquid interface velocity are known to impact microstructure (and defect) development, including potential grain refinement produced by the columnar to equiaxed transition. Thus, a deeper understanding of solidification (and solid state phase transformations, when appropriate) under AM conditions is needed to guide alloy design matched to AM processes. State-of-the-art, multiscale characterization of solidification dynamics and resulting microstructures in the context of the local conditions experienced during AM is needed to achieve this aim. New insights into microstructure development under AM conditions obtained by in-situ/ex-situ characterization of conventional alloys, model alloys, and alloys designed for AM are highlighted. Multiscale in-situ/ex-situ characterization is compared to process modeling and solidification theory and modeling, which will enable the prediction and control of metallic alloy solidification dynamics by advanced manufacturing.

2:35 PM  Keynote
Designing High-temperature Aluminum Intermetallics for Additive Manufacturing: Michele Manuel1; 1University of Florida
    Modern materials contain extraordinary levels of complexity, with components spanning a hierarchy of length scales. Designing materials with complex microstructures and demonstrating unique behaviors would be difficult solely using a reductionist approach to materials development. A powerful utility in this endeavor is the use of multiple, correlative, and scaffolding computational tools. This talk focused on using an integrated materials design approach spanning electronic structure calculations to thermodynamics modeling. Computational techniques are paired with combinatorial experimental methods for validation and exploration to produce a high-temperature aluminum-based, low-cost intermetallic for additive manufacturing.

3:05 PM  Keynote
Advancing Process Control in Metal Additive Manufacturing: Manyalibo Matthews1; 1Lawrence Livermore National Laboratory
    Metal powder-bed fusion (PBF) additive manufacturing (AM), while continuing to play an important strategic role across a diverse application space, still lacks the necessary control to obtain parts that meet strict performance-driven criteria for qualification and certification. Here, a new science-based approach is described which can address this shortcoming and fundamentally transform metal PBF AM through development of a modeling and experimental framework. Using this framework new materials and local part properties can be realized, thus enabling more flexible metal-based AM design capabilities compared to those that are currently available today. Prepared by LLNL under Contract DE-AC52-07NA27344.

3:35 PM Break

3:55 PM  Keynote
TMS Young Innovator in the Materials Science of Additive Manufacturing Award: The Critical Roles of Keyhole in Laser Powder Bed Fusion: Tao Sun1; 1University of Virginia
    Laser powder bed fusion (LPBF) is the most extensively used metal additive manufacturing technology, owing to its unique capabilities for building parts with high geometry complexity and fine features. In a LPBF process, sparks (i.e. spattered particles) can be observed to follow the laser scanning path, indicating the existence of high-velocity vapor arising from the melt pool. Indeed, strong metal vaporization occurs in LBPF, and the resulting recoil pressure can create a deep vapor depression in the melt pool, which is often referred to as keyhole. Keyhole is a critical dynamic structure feature in LPBF. Here, I will present the direct observation of keyhole dynamics using high-speed high-resolution synchrotron x-ray imaging. Based on the morphology and fluctuation mode, keyholes can be categorized as stable and unstable types. Their effects on the effective laser absorption, melt pool morphology development, and generation of various structure defects will be elucidated.