Modification Of Texture Component Approach And Its Application On The Compression Textures Research Of AZ31Magnesium Alloy

Due to the limitation of the existing orientation distribution function (ODF) analysis, the texture components approach was modified and firstly applied to the AZ31alloy for more quantitative texture analysis. The multi-pass isothermal compression of AZ31alloy with different initial textures was conducted at moderate temperature. The effect of initial textures on plasticity, and evolution of the microstructures and textures were investigated by OM, TEM, XRD macro-texture analysis and texture component approach. The following results can be concluded:1) The orientation densities of ODF are determined together with volume fractions, scattering half-widths and multiplicity factors of texture components. So it is difficult to correctly compare different texture components by only ODF orientation densities. In contrast, texture components can be quantitatively characterized and compared by (gi,Vi, Ψi).2) The equation for Gauss fiber-type components was revised, and the equation for the fiber textures in magnesium alloys (fiber axis//ND) is simplified.3) The decomposing procedure of texture components was optimized. For better fitness of real texture distributions of magnesium alloys, a group decomposing method on the units of one major components and several auxiliary ones was proposed, which is to decompose the ODF by a multimodal Gauss-type distribution.4) At lower temperatures, initial textures influence deformation mechanism and DRX of AZ31alloy, thus affect the subsequent deformation ability. The specimens dominated by prismatic texture have better ductility than those of basal texture. The effect of initial textures decreases with elevated temperature, owing to the activations of multiple deformation mechanisms. 5) A brittle-ductile transition of ND specimens dominated by basal texture occurs in the range of230～250℃, owing to combination of <c+a>-pyramidal slip and trivial DRX. During compression many grains reoriented to{0°,90°,10°}, thus the basal texture is weakened while prismatic texture is strengthened.6) The ductility of TD specimens dominated by prismatic texture increases significantly in the range of210～230℃. Because the <a>-prismatic slip can accommodate the imposed shape change, lower energy is stored in TD specimens compared with ND, resulted in inhabitation of DRX in TD. During compression, the basal component is firstly strengthened and then weakened whilst the prismatic texture has an opposite trend, which can be attributed to the change of major deformation mechanism from{1012} twinning to prismatic slip.