Transients in Solidification and Solid-State Transformations in Materials during Additive Manufacturing with Complex Thermo-Mechanical Signatures

Sudarsanam Suresh Babu, UT/ORNL Governor's Chair of Advanced Manufacturing Professor, The University of Tennessee, Knoxville

Reception at 3:30 p.m. in the GTMI Atrium

Abstract:

Additive manufacturing enables design and production of structural metallic components with complex geometries. Recent work has shown that, in addition to complex geometries, site-specific microstructures can be achieved through careful control of processing condition at every layer.  The interactions between boundary conditions imposed by component geometry, wide variations of thermal signatures brought about by mode of energy delivery, and composition of the alloys. These phenomena are studied using computer modeling, in-situ monitoring and ex-situ characterization tools.  This talk will review results from two case studies and associated fundamental challenges in extending these methodologies to wide range of alloys. First, control of crystallographic texture, during electron beam powder melting of Inconel 718 alloy, was achieved by controlling thermal gradient (G) and liquid-solid interface velocity (R). The sensitivity of columnar to equiaxed transitions in solidification maps was related to uncertainty of parameters used in the interface response function theories, as well as, spatial and temporal variations in G and R.  Second study focused on using laser melting experiments and post-process heat treatment as an alloy evaluation methodology.  Microstructures in the melt regions of model Al-12Ce alloy confirmed the feasibility of selecting wide range of solidification microstructures through spatial variations of G and R along the 3D melt pool surface, as well as, stability of eutectic structures during post-process heat treatments.  Extension of the above approach to solid-state additive manufacturing will also be introduced.

Biography:

Dr. Babu obtained his bachelors degree in metallurgical engineering from PSG College of Technology, Coimbatore, INDIA and his master’s degree in industrial welding metallurgy-materials joining from Indian Institute of Technology, Madras. He obtained his PhD in materials science and metallurgy from University of Cambridge, UK in 1992. He also worked as a research associate in the prestigious Institute for Materials Research, Sendai, Japan before joining ORNL in 1993.  From 1993 to 1997, he held joint researcher position with ORNL, University of Tennessee and The Penn State University.   From 1997 to 2005, he worked as an R&D staff at ORNL.  From 2005 to 2007, Suresh held a senior level technology leader position in the area of engineering and materials at Edison Welding Institute, Columbus, Ohio.  From 2007 to 2013, Suresh served as Professor of Materials Science and Engineering and Director of NSF I/UCRC Center for Materials Joining Science for Energy Applications, at The Ohio State University. In 2013, Suresh was appointed as UT/ORNL Governor’s chair of advanced manufacturing at the University of Tennessee, Knoxville, TN. In this role he acts as a bridge to the ORNL’s expertise and infrastructure including manufacturing demonstration facility to develop a collaborative research and education ecosystem locally and deploy engineering solutions to manufacturing industries.  Dr. Babu has published 190 journal papers and numerous conference proceedings.  He has received many awards in recognition of his technical and leadership service to the materials and manufacturing community. He is a fellow of AAAS, ASM International and AWS. 

In the last three years, Suresh has been instrumental and part of the team in securing UTK and ORNL’s leadership in NSF and Presidential initiatives related to national network of manufacturing innovation institutes.  With his ability to foster collaborative activities with ORNL associates and UTK faculty, UTK has secured the following projects: NSF/IUCRC center for materials and manufacturing, Powder processing pillar of lightweight innovation for future (LIFT), and Institute for Advanced Composites Manufacturing Innovation Institute (IACMI).

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