No abstract

An oxide dispersion strengthened (ODS) ferritic steel with nominal composition Fe-14Cr-5Al-3W-0.4Ti-0.25Y 2 O 3 -0.6ZrO 2 was produced by mechanical alloying (MA), based on a prealloyed grade Fe-14Cr-5Al-3W steel with the addition of Ti element, Y 2 O 3 and ZrO 2 , and subsequent consolidation by means of field assisted hot pressing (FAHP). The microstructure and the mechanical properties were analyzed and compared with a reference material with nominal composition Fe-14Cr-5Al-3W-0.4Ti-0.25Y 2 O 3 . The addition of zirconia increased the volume fraction of the smallest and equiaxed ferritic nano-grains and decreased the quantity of larger aluminum nano-oxides within the ferritic matrix, promoting the formation of fine zirconium nano-oxides and leading to the enhancement of the mechanical properties of the alloy.

No abstract

International audienceOxide dispersion strengthened (ODS) Fe alloys were produced by mechanical alloying (MA) with the aim of developing a nanostructured powder. The milled powders were consolidated by spark plasma sintering (SPS). Two prealloyed high chromium stainless steels (Fe–14Cr–5Al–3W) and (Fe–20Cr–5Al+3W) with additions of Y2O3 and Ti powders are densified to evaluate the influence of the powder composition on mechanical properties. The microstructure was characterised by scanning electron microscope (SEM) and electron backscattering diffraction (EBSD) was used to analyse grain orientation, grain boundary geometries and distribution grain size. Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) equipped with energy dispersive X-ray spectrometer (EDX) were used to observe the nanostructure of ODS alloys and especially to observe and analyse the nanoprecipitates. Vickers microhardness and tensile tests (in situ and ex situ) have been performed on the ODS alloys developed in this work