Abstract:Different grain sizes, different feature sizes of H62 brass foil was studied by micro tensile test, the effects of grain size and specimen size on the deformation behavior of material?characteristics was analyzed.With the decrease of the grain size, tensile yield stress increases, grain size effects on the yield stress satisfy Hall-Petch fine grain strengthening relations.Yield strength first decreases and then increase with the thickness decreases, and enhanced with the decrease of the width.Crystal plasticity theory, the surface layer model can the phenomenon of explain the elongation rate, tensile strength increases with the increase of specific surface area.Based on the experimental data of a micro plastic forming establishing micro-plasticity constitutive model by correcting bilinear models.