Crystal anisotropy of AZ31 magnesium alloy under uniaxial tension and compression
(1. Key Laboratory of Disaster Prevent and Structural Safety, Guangxi University, Nanning 530004, China;
2. School of Vocational & Technical Education, Guangxi University of Science & Technology, Liuzhou 545006, China;
3. College of Mathematics and Information Science, Guangxi University, Nanning 530004, China;
4. School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China;
5. College of Transportation Equipments and Ocean Engineering, Dalian Maritime University, Dalian 116026, China)
2. School of Vocational & Technical Education, Guangxi University of Science & Technology, Liuzhou 545006, China;
3. College of Mathematics and Information Science, Guangxi University, Nanning 530004, China;
4. School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China;
5. College of Transportation Equipments and Ocean Engineering, Dalian Maritime University, Dalian 116026, China)
Abstract: To investigate the deformation twinning and the plastic anisotropy of the hexagonal-close-packed (HCP) single crystal, the crystal plastic constitutive model including slip and twinning deformation was established with finite element method based on crystal plasticity theory. The model was verified by test data. Newton-Raphson iteration method was developed with the stress components directly as the basic variables of iteration. The plastic deformation behavior of single crystal AZ31 alloy was analyzed numerically under monotonic tension and compression, respectively, in four different strain paths (i.e. along , , á0001？ and ) with this model. The stress-strain curves were obtained in the above paths. The numerical calculation results show that this crystal model is feasible to predict the activity of slip/twinning system and to describe the number of active twin variants, the types of dominant twin variants and twin intersection. Due to the polar nature of mechanical twinning in inelastic deformation of the material, the plastic behavior of the single crystal material is demonstrated to be notably anisotropic and high asymmetry.
Key words: AZ31 magnesium alloy; constitutive model; single crystal; deformation twin; twin variant; twin intersection