Damage behaviour of an Al2O3 particle-reinforced 6061 alloy induced by monotonic and cyclic deformation

Abstract

Abstract The influence of damage and its correlation with the failure behaviour is discussed in the light of microstuctural aspects. The failure induced by microstructural mechanisms of the Al2O3-particle reinforced aluminium alloy 6061 under uniaxial tensile as well as under cyclic loading was investigated. The damage behaviour as a function of the strain ε can be correlated with stiffness E(ε). Under cyclic loading conditions the damage increases with the number of cycles and can be correlated with the strain amplitude εa. Furthermore, the damage is associated with crack formation and propagation and the damage evolution depends sensitively on the kind of deformation. The crack formation was detected by metallographic investigations and calculated by numerical methods (FEM), taking the size and shape of particles into account. Generally, damage under mechanical loading is initiated by broken particles and agglomerations of particles. In case of the particulate-reinforced specimens the evolution of damage is quite different for monotonic and cyclic loading conditions but, nevertheless, in both cases the damage parameter is given by inhomogeneities characteristic for the MMC which act as seeds for crack initiation.