Hot ductility of wrought 70–30 cupronickel alloy

Abstract

An investigation is described into the mechanisms controlling hot ductility in 70–30 wrought commercial cupronickel alloys. Ductilities were measured by hot tensile testing and tests were conducted over a range of temperatures and strain rates and for materials of different initial grain sizes. Ductilities were found to change in a complex manner with all these variables. In all cases, failure was due to grainboundary cavitation, but good ductility could be achieved if dynamic recrystallization occurred at grain boundaries during testing. Cavities were found to nucleate at manganese sulphide inclusions, and the distribution of cracked boundaries with respect to the tensile axis was far from uniform. Analysis of the metallographic observations suggests that more than one mechanism of cavity growth operated in the material.