To investigate the relationship between macro-plastic behavior and meso-deformation mechanism of Mg alloy AZ31, the mathematical models for various deformation mechanisms of slip, twinning and detwinning are establish...To investigate the relationship between macro-plastic behavior and meso-deformation mechanism of Mg alloy AZ31, the mathematical models for various deformation mechanisms of slip, twinning and detwinning are established, respectively. Furthermore, in order to capture the Bauschinger effect under cyclic loading, the back stress is introduced into the three independent deformation mechanisms, respectively. Finally, using the above-mentioned model, a new cyclic plastic constitutive model based on the constitutive theory of crystal deformation for magnesium alloy is established. On this basis, the numerical simulation for AZ31 under cyclic loading with the axial strain amplitude of 1.2% is carried out in accordance with the aforementioned crystal plas- ticity theory associated with the representative volume element model. The comparison between the stress-strain curves obtained from the simulation and the experiments shows that the macro- scopic mechanical responses predicted using the proposed model are in good agreement with the experimental results. In particular, the unique characteristics of cyclic macro-plastic behavior observed in the experiments can be satisfactorily captured by the presented crystal plasticity model. At the mesoscale, these features are caused by the alternate occurrence of twinning and detwinning mechanisms. The further analysis of meso-plastic behavior shows that there are het- erogeneous distributions of twinning, stress-strain and stress triaxiality in polycrystal under cyclic loading.展开更多
基金Project （11462002） supported by the National Natural Science Foundation of China Project （2016GXNSFAA380218） supported by Guangxi Natural Science Foundation, China+1 种基金 Project （2014ZDK002） supported by the Open Project of Guangxi Key Laboratory of Disaster Prevention and Structural Safety at Guangxi University, China and Project （Z01） supported by the Science Foundation for Doctorate Research of Guangxi University of Science and Technology, China.
文摘To investigate the relationship between macro-plastic behavior and meso-deformation mechanism of Mg alloy AZ31, the mathematical models for various deformation mechanisms of slip, twinning and detwinning are established, respectively. Furthermore, in order to capture the Bauschinger effect under cyclic loading, the back stress is introduced into the three independent deformation mechanisms, respectively. Finally, using the above-mentioned model, a new cyclic plastic constitutive model based on the constitutive theory of crystal deformation for magnesium alloy is established. On this basis, the numerical simulation for AZ31 under cyclic loading with the axial strain amplitude of 1.2% is carried out in accordance with the aforementioned crystal plas- ticity theory associated with the representative volume element model. The comparison between the stress-strain curves obtained from the simulation and the experiments shows that the macro- scopic mechanical responses predicted using the proposed model are in good agreement with the experimental results. In particular, the unique characteristics of cyclic macro-plastic behavior observed in the experiments can be satisfactorily captured by the presented crystal plasticity model. At the mesoscale, these features are caused by the alternate occurrence of twinning and detwinning mechanisms. The further analysis of meso-plastic behavior shows that there are het- erogeneous distributions of twinning, stress-strain and stress triaxiality in polycrystal under cyclic loading.
