|About this Abstract
||Materials Science & Technology 2011
||Innovative Design and Processing of Gas Atomized Precursor Powders to Generate Nano-Composite Microstructures in Ferritic Stainless Steels
||Iver Anderson, Joel Rieken, Matthew J. Kramer, Robert Odette, Erich Stergar
|On-Site Speaker (Planned)
Oxide dispersion strengthened (ODS) ferritic stainless steel microstructures were processed by a simplified powder-based method. Instead of mechanical alloying, precursor ferritic powders were oxidized in situ using gas atomization reaction synthesis to form a kinetically favored (i.e., Cr-enriched) metastable surface oxide, encapsulating the as-atomized powders. This surface layer became a vehicle to carry oxygen into the as-consolidated alloy microstructure, where heat treatments promoted oxygen exchange between metastable prior particle boundary oxides and dissolved Y and secondary additions. These exchange reactions produced nano-metric Y-enriched oxide dispersoids. Subsequent thermal-mechanical processing promoted optimum strengthening by sub-grain formation. Transmission electron microscopy, high-energy X-ray diffraction, and 3-D atom probe helped characterize the powders and dispersoid evolution to quantify the thermal stability of the composite microstructures. The results indicated the promise for tolerance of ultra-high combustion temperatures and, perhaps, radiation tolerance. Support from the USDOE-FE (ARM program) through Ames Laboratory contract no. DE-AC02-07CH11358 is gratefully acknowledged.
||Definite: A CD-only volume