Prediction of flow curves of very thin brass sheets incorporating size effect in hardening model

Abstract

Due to the size effect, the plastic deformation behavior of very thin sheets is dependent on the ratio of specimen thickness to grain size. The general hardening models used for bulk materials and thick sheets are not applicable for representing the plastic flow behavior of very thin sheets accurately. In the present work, the grain size effect (ratio of sheet thickness to grain size t/d) on flow behavior in uni-axial tension has been studied. Very thin sheet specimens of CuZn36 brass of thickness 50μm, 100μm, 150μm and 200μm have been used in this study. The brass sheets were annealed with different combinations of annealing temperature and time to achieve a large range of t/d ratio (1 to 17). A new hardening model has been developed incorporating the grain size effect on flow stress by determination of strength coefficient as a function of t/d. The predicted curves using the developed hardening model agreed well with the experimental results.