NSF-Europe: High Velocity Forming of Nano/Submicron Grain Size Austenitic Stainless Steels

University Of Texas At Austin, Austin TX

Investigators

Abstract

This NSF-Europe award to University of Texas Austin is to the study poor and inhomogeneous ductility during forming of stainless steels by investigating the effect of carbon content, high velocity forming, and providing a laser treatment that would initiate the formation of a refined austenitic structure from stress-induced martensite. Effects of alloy composition (specifically Carbon, Nitrogen, Chromium, and Nickel content), amount of cold working, and annealing history on the microstructural development of three austenitic stainless steels will be studied by this collaborative effort with academic and industrial scientists from Finland (University of Oulu; AvestaPolarit; Stainless Steel Oy; Laserplus Oy, and Sanmina-SCI). In addition, laser-annealing treatments will be developed to tailor microstructures for further metallographic forming; and the influence of high velocity forming on the mechanical properties of laser annealed stainless steels to achieve higher elongations and lower variations in yield strength will be studied. The research studies should yield information that will contribute towards the development of better steels that exhibit better formability and more uniform microstructures. In-situ Transmission Electron Microscopy use during the annealing cycle of nano/submicron stainless steels would provide real time events. This work will make it possible to systematically correlate chemical composition, microstructure, amount of cold-rolling, annealing profile, average grain size, distribution and texture on the deformation mechanisms operating in nano/submicron stainless steels during high speed formability. Exchange of graduate students, research staff and faculty between USA and Finland would enhance knowledge base and research experiences of these scientists. The planned central facility at the University of Texas at Austin for Transmission Electron Microscopy (TEM) experiments will benefit both undergraduate and graduate students, and would increase exposure to other potential users of TEM.