Experimental Investigation on Strengthening Effect of Cu2O Film in Micro Sheet Forming of Copper

Materials processed using micro-manufacturing technologies exhibit significantly different properties compared to those produced using conventional macro-manufacturing techniques. In this paper, the uniaxial tensile tests were performed on the thin sheet specimens of pure copper to investigate how the sheet thickness impacts the flow stress. The experimental results show a continuous decrease of flow stress as the sheet thickness reduces from 200 to 100 mu m, but an increase of flow stress with further reduction in thickness. Firstly, by introducing the ratio of surface grains, the decrease trend of flow stress was explained on the basis of surface layer model. Secondly, the strengthening effect of Cu2O film was clearly demonstrated by the x-ray diffraction and electrodeposition process. Finally, considering the effects of Cu2O film and free surface layer, the mechanical properties of Cu2O film was studied, which is helpful to explain the material behavior in micro sheet forming.