ANISOTROPY OF YIELDING/HARDENING AND MICROINHOMOGENEITY OF DEFORMING/ROTATING FOR A POLYCRYSTALLINE METAL UNDER CYCLIC TENSION–COMPRESSION
ZHANG Keshi1, SHI Yanke1, XU Lingbo1, YU Duokui2
1.Key Lab of Engineering Disaster Prevention and Structural Safety of China Ministry of Education, Guangxi University, Nanning 530004
2.Aeroengine Institute of Shenyang, Shenyang 110015
Cite this article:
ZHANG Keshi SHI Yanke XU Lingbo YU Duokui. ANISOTROPY OF YIELDING/HARDENING AND MICROINHOMOGENEITY OF DEFORMING/ROTATING FOR A POLYCRYSTALLINE METAL UNDER CYCLIC TENSION–COMPRESSION. Acta Metall Sin, 2011, 47(10): 1292-1300.
Abstract The mesoscopic analyses at a grain level are carried out for a pure copper under symmetrical strain cyclic loading. The Voronoi crystal aggregation which consists of a number of randomly arranged crystal grains is adopted in the analysis as a RVE (representative volume element) of a metal material, and a crystalline plastic model is applied to describe the grain’s mesoscopic constitutive relationship, by which the mesoscopic plastic slipping in anisotropic grain follows the nonlinear kinematic hardening law. Through numerical simulation it is confirmed that the present method can be applied to simulate the hysteresis for a polycrystalline material under cycle loading of different strain amplitudes, and it can be used to estimate the subsequent yield surface shape and its curvature change of the material in the cycle loading process, which are relative with the preloading direction. According to statistical analysis, it is found that the coefficient of variation (COV) for internal axial strain in the macro tension direction of the polycrystalline RVE considerably increases with the cyclic number in the symmetrical strain cycle loading, and the statistical lattice rotating of the material increases with loading cycle number. These results indicate that the internal material’s microstructure will tend to heterogeneity, since the coefficients of variation for the inhomogeneous strain and rotation angle increase with the cyclic number.
Supported by National Natural Science Foundation of China (Nos.90815001 and 11072064), Science Foundation of Guangxi University and Key Project of Guangxi Science and Technology Lab Center (No.LGZX201101)
