Abstract
Metal foils indicates low level fracture strain compared with sheet metal. In this study, the free surface roughening is focused on to clarify the mechanism of ductile fracture for metal foils, since the ratio of surface roughness to thickness become larger compared with sheet metal. Materials used are pure copper, pure aluminum and pure titanium with thickness of 0.05, 0.1, 0.3 and 0.5mm respectively. Free surface roughening and ductile fracture behavior are observed under uni-axial tensile state. As a result, the surface roughening to thickness of metal foils with thickness of 0.05, 0.1mm was larger than that of sheet metals with thickness of 0.3, 0.5mm. In addition, an inhomogeneous FE material modeling is proposed for prediction of surface roughening and necking behavior. In this model, grain size and variation in flow stress of each grain as aspect of mesoscopic material information were considered for modeling of material inhomogeneity. The necking behavior of metal foil can be expressed by inhomogeneous FE material modeling. Therefore, it can be concerned that surface roughening to thickness affects the fracture of metal foil.
