Evaluation of microstructure and mechanical properties of liquid phase diffusion bonded ODS steels

Transient liquid phase bonding (TLPB) was employed to join ODS ferritic steel blocks using an amorphous inset material based on Fe–3B–5Si composition with high vacuum uni-axial hot press. The microstructure and mechanical properties were investigated. The TLPB ODS steel showed rather homogeneous distribution of the insert material elements at joined region, while Y–Ti–O precipitation and grain growth up to 20 μm occurred at the region. The TLPB ODS steel had a fairly good tensile strength, which was up to 90% of base material, at temperatures from room temperature to 700 °C. However, it showed poor elongation and impact fracture energy compared to base material, which is considered to be due to the existence of Y–Ti–O precipitate at bonding interface and large grained insert material.