Influence Of Rolling Path On The Texture Evolution And Mechanical Properties Of Mg-2Zn-1.2Ca Alloy Sheets

The cross rolling alternately along the RD and the TD followed by annealing is valid to improve the formability of Al and Mg alloy plates through tailoring the texture,which already achieved good results.And the addition of rare-earth(RE)elements or Ca in Mg alloy is one approach for modifying the texture,which was an effective way to enhance the ductility and formability at room temperature.And in these kind of Mg alloys,weak textures with basal poles tilting away from ND to TD are usually developed,which exhibited high elongations and excellent formability at ambient temperature.However,these plates with double-peak textures show a strong planar mechanical anisotropy contributing to significant differences in ductility and strength if the external stress imposed along the rolling direction(RD)and the TD,respectively.Hence,it is easy to generate earring during forming procedure.In the present study,we designed a Mg-2Zn-1.2Ca alloy and combining the usage of many advanced characterization techniques(e.g.XRD?EBSD and SEM)and mechanical property tests(e.g.tensile test)during different hot/cold rolling path and subsequent annealing and the relationships between the texture distribution and forming ability were systematically investigated.And the research disclosing the rolling paths how to affecting deformation microstructure and crystallographic orientation of recrystallized.The results show that:(1)The rolling path greatly affects the annealed texture.The unidirectional rolling develops a texture with basal poles mainly distributing along the TD.By contrast,an ellipse-like(0002)texture with basal pole inclining largely away from the ND is developed after hot cross rolling and annealing.(2)In the hot cross rolling experiment,this ellipse-like texture could not reserve during the subsequent unidirectional hot rolling and annealing.Both of UR and CR plates exhibit a strong planar mechanical anisotropy compared with the traditional unidirectional rolled plate.By contrast,because of varying the rolling path greatly change the rolling and annealing textures,the UR-RD and CR-RD develops an circle-like(0002)texture with basal pole inclining largely away from the ND.(3)In the unidirectional rolling at ambient temperature and subsequent annealing,the textures with basal poles tilting away from ND to TD change to RD with the total reduction increase.And varying the rolling path greatly change the rolling and annealing textures of Mg-2Zn-1.2Ca plate.(4)Tensile tests show that there is a great difference in yield strength along different directions for the annealed plate with double peaked textures.However,for these with basal poles distributing on a circle largely away from the ND in cold rolling,the anisotropy was reduced.In the cold cross rolling experiment,the elongation of the tensile samples is mainly brittle fracture,which leads to low elongation.