Tensile and fracture characteristics of oxide dispersion strengthened Fe─12Cr produced by hot isostatic pressing

Abstract

The mechanical characteristics of a model oxide dispersion strengthened (ODS) alloy with nominal composition Fe─12 wt%Cr─0.4 wt%Y₂O₃ were investigated by means of microhardness measurements, tensile tests up to fracture in the temperature range of 298─973 K, and fracture surface analyses. A non-ODS Fe─12 wt%Cr alloy was also studied to assess the real capacity of the oxide dispersion for strengthening the alloy. The materials were produced by mechanical alloying followed by hot isostatic pressing consolidation and heat treatment at 1023 K. The strengthening effect of the oxide nanodispersion was effective at all temperatures studied, although the tensile strength converges towards the one obtained for the reference alloy at higher temperatures. Moreover, the ODS alloys failed prematurely at T < 673 K due to the presence of Y-rich inclusions, as seen in the fracture surface of these alloys.