Research on the Micro-tensile Test on H62 Brass Sheet and Size Effects

In order to investigate the effect of grain size and thickness with respect to material mechanical property in the micro-scale, experiments were taken by tensile test on H62 brass sheet metal with different grain sizes and thicknesses. The experiment results show that the flow stress decreases with the decreasing sheet metal thickness, and the flow stress decreases as grain size increases. It also shows that the hardening exponent of sheet metal increases as sheet thickness and sheet grain sizes increasing respectively. A parameter φ=t/d(the ratio of sheet thickness to material grain size) was introduced to characterize size effects, then, a new constitutive model, which consider the factor φ, was developed by combining the surface layer theory and the Swift model. A good coincidence was obtained between the proposed model and experimental results. This investigation can provides some support for theoretical and experimental study of micro-forming.