Al-4.6%Cu合金の延性と破壊特性におよぼす冷間加工と時効の影響

抄録

The influence of cold work and aging on the ductility and the fracture behaviour of high purity Al-4.6%Cu alloy has been investigated to improve the low ductility of the alloy. Marked improvement in the ductility of coarse grained Al-4.6%Cu alloy can be attained by proper cold working and aging after solution treatment, and fracture mode changes from brittle grain boundary fracture to ductile transgranular fracture. These phenomena can be observed if cold work were immediately carried out after solution treatment. Preaging treatment after quenching is undesirable because of a marked decrease of ductility. The cause of the marked improvement in ductility is attributed to the absence of precipitate-free zones along grain boundaries, supression of coarse grain boundary precipitates and the precipitation of coarse intermediate precipitates (θ′ phase) in the matrix.