YTTRIA REINFORCED FE-CR FERRITIC ALLOY BASED NANOCOMPOSITES FOR FUSION REACTOR STRUCTURAL APPLICATIONS

Abstract

Ferritic steel with oxide dispersion strengthening (ODS) is a promising material for fusion and fission reactor components. In this study, the influence of Zr, V, Mo on yttria dispersed ferritic alloys was analysed. The powders were developed by using mechanical alloying (MA) and subsequently consolidated by spark plasma sintering (SPS) at different temperatures (900°C, 1000°C & 1050°C) in argon atmosphere. The densification of the alloys was found to improve significantly with increase in the sintering temperature. The maximum relative density was found to be 97.5-98.3% with samples sintered at 1050°C. Microstructural analyses, carried out by optical and scanning electron microscopy (SEM), showed random orientation of grains with bimodal grain size distribution. X-ray diffraction phase analysis showed the presence of bcc ferritic phase in which Y-Ti-O, TiO and Ti-Cr-O oxides were dispersed and this was confirmed through transmission electron microscopy (TEM). Further, the hardness value obtained by nanoindentation was correlated with the compressive strength and wear resistance. The results have been analysed in terms of alloying and strengthening mechanisms