2013 Volume 54 Issue 6 Pages 984-989
Size effects are the main problem in micro-forming process and material behavior with miniaturization of feature size. In the paper, size effects of grain size and foil thickness on deformation behavior and fracture were investigated by using micro tensile test of SUS304 foil. The results show that the yield strength of SUS304 stainless foil increases with the decrease of foil thickness and grain size in micro tensile tests. Meanwhile, the fracture mechanism of SUS304 foil changes from ductile fracture with lots of dimples to ductile fracture with slip separation with the decrease of foil thickness. A compound material model by considering grain size, foil thickness and surface effects is proposed and constitutive relation of SUS304 foil is established. The calculation curves well match with experimental results.