Graduate Student Seminar

October 27, 2023

12:00 p.m. ET

Scaife Hall 105

Process Control in Metal Additive Manufacturing

High cooling rates and feedstock material based on casting alloys create the conditions for nonequilibrium and often nonideal solidified microstructures during laser powder bed (LPBF) fusion additive manufacturing. Furthermore, the geometric complexity of metal 3D printed LPBF objects is typically associated with changes in thermal boundary conditions that drives the need for voxel-level thermal process control. Using a combination of predictive models for themesoscale melt pool dynamics, thermal history, grain nucleation models and spatiotemporal laser energy control, we show that the net processing conditions can be tailored to produce more optimal material structure and properties. Furthermore, precise laser energy control as a function of thermal boundary conditions will be shown to also limit macroscale defects in LPBF, further enhancing part-scale properties and performance. Additional topics in LPBF will be discussed including in situ process monitoring, functionally-graded material processing and micro lattice fabrication. A brief introduction to Materials Science Division research at LLNL will also be presented. Prepared by LLNL under Contract DE-AC52-07NA27344.

Manyalibo (“Ibo”) Matthews, Lawrence Livermore National Laboratory

Dr. Manyalibo (“Ibo”) Matthews currently serves as Division Leader of the Materials Science Division of the Physical & Life Sciences Directorate at Lawrence Livermore National Laboratory. He earned his Ph.D. in Physics from M.I.T. and his B.S. in Applied Physics from U.C. Davis. Prior to LLNL he was Member of Technical Staff at Bell Laboratories in Murray Hill, N.J. where he led a research team developing next generation optical materials and networks. Dr. Matthews has published over 175 peer-reviewed articles with >13,000 citations, three book chapters, holds 20 U.S. Patents and is a Fellow of the Optical Society of America.

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