Deformation behavior of materials in micro-forming with consideration of intragranular heterogeneities
(College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China)
Abstract: To describe the relationship between the whole material deformation behavior and each grain deformation behavior in micro-forming, experimental and numerical modelling methods were employed. Tensile test results reveal that contrary to the value of flow stress, the scatter of flow stress decreases with the increase of thickness-to-grain diameter (T/d) ratio. Microhardness evaluation results show that each grain owns unique deformation behavior and randomly distributes in each specimen. The specimen with less number of grains would be more likely to form an easy deformation zone and produce the concentration of plastic deformation. Based on the experiment results, a size-dependent model considering the effects of grain size, geometry size, and the deformation behavior of each grain was developed. And the effectiveness and practicability of the size-dependent model were verified by experimental results.
Key words: micro-forming; deformation behavior; size effect; model; intragranular heterogeneity