| The automobile,war and aerospace industry will utilize outstanding lightweight materials in order to respond to the call of“Green China”.Magnesium alloys are the lightest structural metallic materials and show great potential for those fields.However,wide industrial application of magnesium alloys are hindered because of their poor room temperature fomability caused by a strong c-axis//ND basal-type texture.Commercial AZ31 magnesium alloy was exthrued to 2mm and pre-deformation and subsequent annealing are carried out to improve the basal-type texture.The primary research contents are listed as follows:?1?It was seen that the four-peak texture along ED can be constructed by pre-compression technology using plate compression die along ED of conventional extruded AZ31 sheet,it can induced{10<sub>12}tensile twins,and the four-peak texture was retained after annealing with the c-axis of grain deflecting from ED to ND at a small angle.The texture components with smaller angle between grain c axis and ND are the residual basl slip soft orientation,while those with larger angle are induced by the twin.?2?With the increase of pre-compression strain along ED,the proportion of strength of four-peak texture will change.And the ratio of orientation induced by twinning increased,thereby the cupping ability of sheet also increase.When pre-compression increased to 6%,many twins were introduced to coordinate deformation.The forming property of the annealed sheet is the best,and the cupping value reaches 4.0 at room temperature,which is about 67%higher than that of the extruded sheet?2.4?.However,decrease of the forming ability can be observed with increasing pre-compression strain.This is because the large in-plane anisotropy of the sheet.When the pre-compression strain reaches to 9%,the structure almost completely twins,and a strong c-axis//ED texture is formed after annealing.?3?“Pre-compression and annealing”and“pre-stretching”processes were both conducted on c-axis?ND textured AZ31 sheet.The orthogonal four-peak texture around ND was introduced successfully,but the orthogonality was weakened after annealing.The results show that the room temperature formability of 8%pre-pressing annealing and 10%pre-stretching annealing sheets are the better,and the cupping value is 3.8,which is up to 65%compared with the original sheet?2.3?.?4?Based on the above experimental results,it is found that the symmetry of texture may also affect the properties of sheets.Before studying the texture symmetry,it is necessary to determine the spatial orientation of the c-axis of grains,so the spatial orientation??,?,??is determined in this study,which will provide some help for the discussion of texture symmetry in the future.Among them,?is the angle between the projection of the c-axis on the ED-TD plane and ED,?is the angle between the projection of the c-axis on the ED-TD plane and TD,and the?is the angle between c-axis and ND,respectively.The results show that the more dispersed?and?are,the better the texture symmetry is. |
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