Mechanical Properties of Neutron Irradiated Nano-structured Ferritic Alloy 14YWT

Abstract

Advanced nano-structured ferritic alloys (NFAs) containing a high density of ultra-fine (2-5 nm) nanoclusters enriched in Y, Ti, and O are considered promising candidates for structural components in future nuclear systems. The microstructure of a NFA is composed of nanometer sized regions rich in Y, Ti, and O uniformly distributed in a ferritic matrix. The high number density of nanoclusters in NFAs are responsible for their superior tensile strengths compared to conventional ODS ferritic alloys and may provide effective trapping centers for point defects and transmutation products produced during neutron irradiation. This paper summarizes the mechanical properties of an advanced NFA, designated 14YWT, currently being developed at Oak Ridge National Laboratory. For this study an identical alloy to 14YWT, designated 14WT, was produced without nanocluster dispersions in order to quantify the effect of the nanoclusters on mechanical properties. This report summarizes preliminary tensile and fracture toughness data for 14YWT and 14WT irradiated at 300, 580, and 670� to ~1.5 displacements per atom.