Research On The Effect Of Texture On Cold/Warm Rheological Behavior Of AZ31 Mg Alloy With Deformation

Magnesium alloy after plastic deformation is easy to produce strong base texture,easy to lead to the yield strength of anisotropy and tension-compression asymmetry,and such anisotropy is more significant in the low temperature range.Therefore,the study on the effect of texture on the cold/warm rheological behavior of wrought magnesium alloy can provide important data reference for the selection of cold/warm plastic deformation process and the optimization of property texture.In this paper,extruded AZ31 magnesium alloy bars and pre-compressed magnesium were prepared by extrusion and pre-compression process and subsequent annealing process.Cold/warm tensile tests were carried out on samples with different initial orientations.On this basis,the cold/warm constitutive equations and processing diagrams of different initial orientations were established.And system to study the texture and deformation conditions on the rheological curve,strain hardening curves and deformation in the process of organization,the influence of the texture evolution,deformation mechanism and the qualitative analysis of texture and the influence of deformation condition,finally using viscoplastic self-consistent model(VPSC)quantitative analysis of the state extruded AZ31 magnesium alloy deformation mechanism in the process of plastic deformation.Firstly,using extruded AZ31 magnesium alloy rods and precompressed AZ31magnesium as raw materials,tensile tests were carried out on the samples in the extruded magnesium alloy direction(ED),transverse(TD)and precompressed magnesium alloy direction(CD)at 20??350?and strain rate of 10^-3?1s^-1.The constitutive equations under the influence of different texture configurations were established,and the effects of texture and deformation conditions on rheological behavior and work hardening behavior were studied.With the increase of temperature and the decrease of strain rate,the difference of tensile rheological curves of different texture configurations also decreases.With the increase of temperature and the decrease of strain rate,the work hardening rate decreases.Then,the cold/temperature processing maps with different orientations were drawn,and the microstructure of samples with different texture configurations and deformation conditions were observed.The results show that the extruded magnesium alloy has obvious tension and compression properties at room temperature,and a large number of tensile twins are produced during compression.The texture changes of the samples with different orientations are obviously different during the tensile deformation process.The silk texture remains obvious in the ED,and the texture changes obviously in the Td and Cd directions due to the formation of the tensile twins.The activation amount of the tensile twins decreases gradually with the increase of the deformation temperature.Finally,VPSC was used to numerically simulate the tensile and compression behavior of extruded AZ31 magnesium alloy bars in the ED at room temperature and the tensile and rheological behavior of different orientations.The deformation mechanism under the influence of the deformation conditions and texture during the plastic deformation process was quantitatively analyzed.The results show that in the ED at room temperature,the deformation is mainly caused by basal plane slip and cylindrical slip,while in the room temperature compression,the deformation is mainly caused by basal plane slip and tensile twins.For the extruded AZ31magnesium alloy,the deformation along the ED at different temperatures is mainly dominated by the slip of the base plane,and the activation activity of the tensile twins is very small and close to zero.Tensile deformation along the TD at different temperatures is dominated by the slip of the base plane.At lower temperature,the twins have some activity at the initial stage of deformation,and the activity of the twins gradually decreases with the increase of temperature.When the temperature is above 200?,the slip of the cone no longer participates in the tensile deformation of the samples in the ED and TD.