Solid State Diffusion Bonding of ODS Eurofer Steel by Spark Plasma Sintering

Abstract

Oxide dispersion strengthened (ODS) steels are considered to be one of the candidate structural materials for advanced nuclear applications due to their high elevated-temperature strength, corrosion resistance, and radiation tolerance. Joining of ODS steels by traditional fusion joining techniques is not applicable, because the melting process results in the coarsening of fine grains and agglomeration of nanosized oxide particles, and consequently a significant loss of strength. Spark plasma sintering (SPS) has recently been employed as a novel joining technique, which could be beneficial for joining ODS steels considering the solid state characteristic. A powder metallurgy prepared ODS Eurofer steel was successfully joined using SPS. The microstructure and mechanical properties of the joints were investigated. An almost defect-free joint was obtained at the selected processing condition. The tensile properties of the joints are comparable to the base material. Fracture analysis shows an intergranular fracture in the as-joined sample, while a ductile fracture with well-defined dimples is found in the tempered sample.