Hierarchical-microstructure based modeling for plastic deformation of partial recrystallized copper

摘要

Hierarchical microstructure in partial recrystallized materials can simultaneously improve the strength and ductility of metallic materials. Modeling the mechanical behavior of partial recrystallized materials helps to process materials with superior combination of ductility and strength. Here, using experimental characterization, cellular automation (CA) and finite element method, hierarchical-microstructure based modeling was proposed to simulate the tensile deformation of partial recrystallized copper. Firstly, partial recrystallized coppers with different volume fractions of recrystallization were produced by means of extrusion machining and subsequent heat treatment (HT). Uniaxial tensile tests and microstructural observations show that the hierarchical-microstructure of recrystallized grains (RGs) surrounded by elongated subgrains has a significant effect on the mechanical properties. Then, based on the experimental results, a hierarchical-microstructure based plasticity model was developed to describe the yield surface of partial recrystallized materials. CA was further employed to simulate the hierarchical microstructure. By embedding the plasticity model and simulated hierarchical-microstructure in finite element method, a finite element model (FEM) for mechanical behavior of partial recrystallized copper was proposed, where the elongated subgrain with forest dislocation and low angle grain boundary, the RG with few dislocations and twin boundary, and volume fraction of recrystallization were taken into consideration. Finally, the experimental data and the comparison with the conventional plasticity model validate the rationality of the proposed model.