Papers by Keyword: Texture

Abstract: Possibilities of X-ray methods, using diffractometric measurements of X-ray line profiles and crystallographic texture, are compared as applied to study of SPD metal materials. The texture analysis gives the most direct data on the degree of grain fragmentation under conditions of deformation. The consideration is illustrated by results, obtained by X-ray studies of ECAP rods from Cu and Ti.

Abstract: All the SPD techniques introduce reversal straining principally, but effects of the reversal deformation on structure evolution were not studied directly yet. In the present work, an attempt was made to manage structure in pure (99.99%) Al by strain reversal through high pressure torsion (HPT). Total accumulated deformation up to equivalent strain ~8 was used. General trend of the grain refinement is similar for both deformation modes; and it is typical with all other SPD processed FCC metals. At the same time, the difference in microstructure evolution at the vicinity of the specimen axis and with increasing distance in the radial direction introduces microstructural heterogeneities which are specific features of the reversal straining. In the monotonic deformation process the A ({111}<011>) fiber is gradually substituted by the C component ({ 0 0 1}< 1 1 0>) with increasing strain before it is found to weaken. In the reverse straining process the A fiber is found to dominate the deformation texture in the low strain region. In the reverse straining process at high strain level, a {001}<100> component appear.

Abstract: In the appearance design of a product, the designer should combine his/her creative thinking with the industrial design approaches and skills to carry out the creative design from the aspects of product’s shape, color and texture, etc. However, from the viewpoint of the brand, a company or a product should have its own unique style of appearance. How to balance the creativity of designer and the original style is often a contradiction in product design. Based on this consideration, this paper presented a concept of Inheriting Degree (ID) in product appearance design. The visual characteristics of the product appearance were analyzed first and the hierarchical system for ID in product appearance design was established. The idiographic indexes of ID were given for a product’s appearance in shapes, colors and textures, respectively. By introducing set theory, the mathematical models were established and calculation formulae for each kind of ID were proposed. The results of this paper would provide a theoretical foundation for designer to generate design concepts in brand products. It also would provide a guideline for the development of computer aided design and evaluation system for the appearance design of brand products.

Abstract: The anisotropy in mechanical strength and electrical conductivity in Cu-Ag alloy during cold rolling were investigated. The anisotropy in tensile strength and electrical conductivity was significant with increasing Ag content in Cu-Ag alloy. The cold rolled Cu-Ag alloys with higher Ag content have filamentary structure, which is composed of elongated eutectic phase and Cu matrix. In addition, the eutectic phase in Cu-Ag alloys with higher Ag content has a strong α-fiber texture. It can be mentioned that the eutectic phase in filamentary structure is promotes the anisotropy of electrical conductivity of Cu-Ag alloys. This strong a-fiber texture of eutectic phase was decreased by annealing process (300 OC for 1h), and the anisotropy in strength and conductivity was decreased.

Abstract: In order to secure the uniformity and to reduce the scattering of torque coefficient value, which is a decisive factor in the quality of high tension bolt nut and washer sets, effort is required from the manufacturer to standardize manufacturing process and to continuously improve the quality.

Abstract: The aims of this study are to investigate the microstructure evolution of AZ31 Mg alloys with normal rolling and cross rolling as the large strain hot rolling affects microstructure, texture and mechanical properties of AZ31 Mg alloys. In the microstructures of as-rolled both samples, twins are clearly apparent, small and recrystallized grains are visible along some grain boundary and twinned regions. The Lankford values of large strain cross rolled sample obviously demonstrate the higher average r-value and lower planar anisotropy value. The press formability of cross rolled Mg alloy might be improved due to control of texture and grain size by severe deformation.

Abstract: High-energy synchrotron diffraction offers great potential for experimental study of recrystallization kinetics. A fine experimental design to study the recrystallization mechanism of Interstitial Free (IF) steel was implemented in this work. In-situ annealing process of cold-rolled IF steel with 80% reduction was observed using high-energy X-ray diffraction. Results show that, the diffraction intensity of {001}<110> and {112}<110> belong to α-fiber texture component decreased with the annealing temperature increased while {111}<110> did nearly not change and {111}<112> increased; the FMTH decreasing and d-space changing with annealing temperature increasing indicated that the residual stress relaxed completely during recovery.

Abstract: Y3Al5O12:Nd3+ nanoceramics were obtained by sintering nanocrystalline Y3Al5O12:Nd3+ powders at 450 oC under different pressures between 2 and 8 GPa. The structural purity, residual stress, strain, texture, and crystallite size of the products were analysed with X-ray powder diffraction. The results indicate that the average crystallite size remains unchanged at about 30 nm in spite of the heating and the pressure applied. No texture was observed. On the other hand, the microstrains increase with increasing pressure, while the residual stresses are at their maximum in the green body and the sample processed at 8 GPa. Increasing strains were observed to increase the width of the luminescence lines and to decrease the luminescence decay times.

Abstract: The stored energy distribution versus crystal orientation in polycrystalline copper was determined using synchrotron radiation. This distribution is an important input data for recrystallization models. The stochastic vertex model of recrystallization was used in the present work. It is a mixture of the classical vertex model and the Monte Carlo algorithm. Both grain boundary energy and stored energy are taken into account in the calculations. In each elementary step, a reasonably small, random modification of a given vertex position is generated and a corresponding total energy change of a system is calculated. A new vertex position is retained with a probability proportional to the Boltzmann factor. In such a way one avoids solving a complex system of equations. This approach is also closer to the stochastic nature of recrystallization process. The inclusion of the stored energy distribution in the above model enables a good explanation of the recrystallization process. The recrystallization textures for polycrystalline copper rolled to low and high reductions were predicted in agreement with experimental results.

Abstract: A method is presented by which all components of Fij(ϕ, ψ, hkl) belonging to the same measurement direction and reflection can be determined. The neutron measurements are to be done with a single specimen, shaped as a cuboctahedron. An apparatus for producing a compressive stress state in the specimen is needed. It must be small enough to fit into the neutron goniometer and to allow movement of the goniometer to all Eulerian angles. Using this set-up the tensors F(ϕ, ψ, hkl) can be measured for any ϕ, ψ and (hkl).