HOT TENSILE CHARACTERISTICS AND MICROSTRUCTURE OF A CU-0.65CR-0.08ZR ALLOY FOR FUSION-REACTOR APPLICATIONS

Tensile tests were carried out at different temperatures covering a wide temperature range from 20 to 750-degrees-C on a heat treatable Cu-0.6 wt% Cr-0.08 wt% Zr alloy of interest for nuclear fusion reactor application as primary heat sink material. The alloy shows good strength properties up to 500-degrees-C. Just above this temperature, a drop in the 0.2% yield strength, a reliable indicator of a softening process, occurs. A loss in ductility is observed at intermediate temperatures with a minimum (elongation to rupture = 5.5%) at 550-degrees-C. This embrittlement, according to microstructural investigations (optical microscopy and scanning electron microscopy) on several deformed specimens, is due to an intergranular cracking process, which is typical of several copper alloys when hot deformed.