Misorientation between neighboring grains has significant influence on migration of grain boundaries during annealing of cold worked polycrystalline materials (1,2). The migration of grain boundaries could lead to formation of unique textures and improvement of materials properties (3). Therefore,characterization of the misorientation distributions is crucial for understanding underlying mechanisms.Based on group theory and the assumption of random orientation distribution, MacKenzie (4,5)calculated the distribution of misorientation angles and rotation axes in polycrystalline materials withcubic symmetry. A Similar study was reported by Morawiec (6) for materials with other crystalsymmetries. Recently, the EBSD (Electron Back Scattering Diffraction) technique was successfullyutilized to determine misorientation distributions between grains in either randomly or preferentiallyoriented polycrystalline materials (1-3). However, theoretical characterization of the misorientationdistribution in materials with strong texture remains a challenge. The study of textured materials wouldhave practical impact in industry, especially in the case of grain boundary migration during recrystallizationof heavily deformed matrix. In the present work, a new method is presented for calculating themisorientation distribution in textured polycrystalline materials.

The misorientation distributions in deformed and recrystallized polycrystalline aluminum were calculated and analyzed basedon the orientation distribution function (ODF) data. The calculation result was a very good statistical description of themisorientation distribution between neighboring grains. The calculated distributions consist of a random part and a characterizedpart, of which the characterized part represents the major characteristics of the corresponding misorientation distribution. Therepresentability of calculated misorientation distribution is discussed.

In comparison with the rolling texture modeling based on the Sachs, Taylor and modified Taylor assumptions a modified Sachs model was proposed, in which the equilibrium of both stresses and strains among the deformed grains is considered and therefore the shear strains are partially constrained by activation of other slip systems besides the primary one. The modeling predicts more details of the rolling texture that observed frequently in rolling aluminum sheets, and the model calculation could include the influence of initial texture. The parameters for homogeneous rolling are reported and the shear texture formation is also discussed.

We present plane strain simulations about the dependence of orientational in-grain subdivision and crystallographic deformation textures in aluminum polycrystals on grain interaction. The predictions are compared to experiments. For the simulations we use a crystal plasticity finite element and different polycrystal homogenization models. One set of finite element simulations is conducted by statistically varying the arrangement of the grains in a polycrystal. Each grain contains 8 integration points and has different neighbor grains in each simulation. The reorientation paths of the 8 integration points in each grain are sampled for the different polycrystal arrangements. For quantifying the influence of the grain neighborhood on subdivision and texture we use a mean orientation concept for the calculation of the orientation spread among the 8 originally identical in-grain orientation points after plastic straining. The results arecompared to Taylor-Bishop-Hill-type and Sachs-type models which consider grain interaction on a statistical basis.The study reveals five important points about grain interaction. First, the consideration of local grain neighborhoodhas a significant influence on the reorientation of a grain (up to 20% in terms of its end orientation and its orientationdensity), but its own initial orientation is more important for its reorientation behavior than its grain neighborhood.Second, the sharpness of the deformation texture is affected by grain interaction leading to an overall weaker texturewhen compared to results obtained without interaction. Third, the in-grain subdivision of formerly homogeneous grainsoccurring during straining is strongly dependent on their initial orientation. For instance some crystals build up ingrainorientation changes of more than 20°after 95% straining while others do practically not subdivide. Fourth, thedependence of in-grain subdivision on the neighbor grains is different for crystals with different initial orientation (cubeor rotated Goss grains reveal strong subdivision). Fifth, the upper bound for the variation of texture due to changes ingrain neighborhood amounts at most to 5% in terms of the positions of the main texture components. In terms of theoverall orientation density all predictions (using different neighborhood configurations) remain within a narrow tubewith an orientation scatter of 10% (β-fiber) to 20% (Brass component, α-fiber) when the neighborhood changes.

出了一种考虑反应应力的体心立方金属塑性变形模型，计算了位错开动所造成的切应变及可能会引发的反应应力，并使之影响到后续的位错开动过程。在{110}和{112}两类滑移面上的临界切应力比为0.95，第2位错与第1位错取向因子差小于5%，第2位错也同时开动的条件下计算了体心立方金属冷轧80%时的变形织构。结果表明，所计算的织构比以往其他计算模型更接近冷轧80%无间隙原子钢板的实际织构。分析认为，该模型可以兼顾多晶体塑性变形时应变与应力的连续性，因而更接近于体心立方金属变形的真实晶体学过程。