Fatigue crack behaviour in solution treated Cu-35%Ni-3.5%Cr

Crack initiation and propagation have been investigated in solution treated Cu-35% Ni-3.5% Cr (weight percent) under cyclic loading with constant stress amplitude. Grain boundaries were found to be favourable sites for crack initiation. The crack density at fracture increases with increasing stress amplitude, is obviously controlled by cyclic plastic deformation, and can be correlated with the lifetime. Under fatigue loading, crack propagation is first intercrystalline and then transcrystalline. The transition from intercrystalline to transcrystalline crack propagation takes place at a stress intensity, which increases with increasing stress amplitude. This crack behaviour has been discussed in connection with the pronounced planar slip in the material investigated. (orig.)Reprinted from: Materials Transactions, JIM, (1994), v. 35(3) p. 174-181 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman