Properties and Applications of Hot Formed O.D.S. Alloys

Abstract

Oxide dispersion strengthening (ODS) extends the maximum temperature capability of superalloys and can be achieved through the mechanical alloying (MA) of powder feedstock (1) (2) (3). Such a solid state processing route produces a fine, homogeneous dispersion of yttrium oxide into a segregati on freematrix, the absence of any melt solubility restrictionsena bling the alloy base to betailored to meet other property requirements. Compacted and worked MA alloys further exhibit a unique capacity for secondary recry stallisation to develop coarse grains to further enhance high temperature properties. This type of structural growth is dependent upon the total thermomechanical processing (MP) history through all processing operations, a factor which can be exploited during the hot forming of individual components (4). Here, properties can be derived to specific requirements with more flexibility, and more economically than components machined from mill product bar or sheet. Hot forming is generally applied to ‘unrecrystallised’ feedstock taken at various appropriate stages of mill product processing.