Preliminary results of CuCrZr/316L tube-to-tube junctions fabricated with rotary friction welding

The development of non-melting Cu alloy/steel tube-to-tube welding methods is of significance for the manufacturing of monoblock divertor components for future DEMO. In this study, ITER sized CuCrZr tubes and 316 L tubes, as model materials, were tube-to-tube joined by rotary friction welding (RFW). The microstructure, hardness and tensile properties of the junctions were investigated systematically. The mechanism of micro-defects and fine Cr bands in CuCrZr was illustrated. Post-welding heat treatment (aging) somewhat improved the micro-hardness and tensile strength of the junctions, but its effect on room temperature ductility is negligible. The demonstrated feasibility of RFW implies its potential application for the joining of advanced tubular materials, e.g. oxide dispersion strengthened (ODS) Cu and ODS steel, although some obstacles should be overcome.