Stress relaxation behaviour in bending of high strength copper alloys in the Cu–Ni–Sn system

The microstructure of spinodally hardened, stress relaxation tested Cu–Ni–Sn alloys is characterized. The main mechanism of relaxation is recrystallization. At 150°C, initial stress values of 480–600 N mm−2 cause significant microstructural changes even if up to 90% of the initial stress remains after 1000 h of testing. Elevated temperature stability depends on the uniformity of deformation.