Microstructural effects on tension and fatigue behavior of Cu–15Ni–8Sn sheet

The effects of systematic changes in microstructure/heat treatment on the mechanical behavior of Cu–15Ni–8Sn (Pfinodal®) were evaluated in uniaxial tension and in cyclic strain-controlled fatigue with the use of a modified GE Flex Tester operated to provide fully reversed bending fatigue. The magnitude of cyclic strains was controlled via the use of different diameter mandrels. Smaller diameter mandrels produced higher values of cyclic strain and lower fatigue life. Multiple samples were tested and fracture surfaces were analyzed via scanning electron microscopy. The fatigue results were analyzed via a Coffin–Manson–Basquin approach and compared to fatigue data obtained from the literature, where testing was conducted on similar materials. Significant effects of cold work and heat treatment on both the tension and fatigue behavior were obtained and rationalized based on the mechanisms of failure, revealed by SEM, for this system.