Dr. Mishra (Ph.D. in Metallurgy from University of
Sheffield) is a University Distinguished Research Professor at University of
North Texas. He serves as the Director of a recently launched Advanced
Materials and Manufacturing Processes Institute (AMMPI) at UNT. He is also the
UNT Site Director of the NSF I/UCRC for Friction Stir Processing and a Fellow
of ASM International. He is a past-chair of the Structural Materials Division
of TMS and served on the TMS Board of Directors (2013-16). He has
authored/co-authored 312 papers in peer-reviewed journals and proceedings and
is principal inventor of four U.S. patents. His current publication based
h-index is 64 and his papers have been cited more than 21000 times. He has co-authored
two books; (1) Friction Stir Welding and Processing, and (2) Metallurgy and
Design of Alloys with Hierarchical Microstructures. He has edited or co-edited
fifteen TMS conference proceedings. He serves on the editorial board of
Materials Science and Engineering A, Science and Technology of Welding and
Joining, and Materials Research Letters. He is the founding editor of a short
book series on Friction Stir Welding and Processing published by Elsevier and
has co-authored seven short books in this series.
This study explored solid-state additive friction stir deposition (AFSD) as a modular manufacturing technology, with the aim of enabling a more rapid and streamlined on-site fabrication process for large meter-scale nuclear structural components with fully dense parts. Austenitic 316 stainless steel (SS) is an excellent candidate to demonstrate AFSD, as it is a commonly-used structural material for nuclear applications. The microstructural evolution and concomitant changes in mechanical properties after 5 MeV Fe++ ion irradiation were studied comprehensively via transmission electron microscopy and nanoindentation. AFSD-processed 316 SS led to a fine-grained and ultrafine-grained microstructure that resulted in a simultaneous increase in strength, ductility, toughness, irradiation resistance, and corrosion resistance. The AFSD samples did not exhibit voids even at 100 dpa dose at 600 °C. The enhanced radiation tolerance as compared to conventional SS was reasoned to be due to the high density of grain boundaries that act as irradiation-induced defect sinks.
