Papers by Keyword: Recrystallization Texture

Abstract: Optimized conditions of hot and cold rolling followed by annealing can result in a balance between recrystallization and rolling textures in order to reduce the planar anisotropy of brass sheets. In this work, the effect of finish rolling temperature, cold reduction and annealing temperature on texture development has been investigated. It is shown that uniform deformation at higher finishing temperature is responsible of formation of a severe Cube and G texture components. In contrast, mechanical twinnings are widely formed at low finishing temperatures. There is also a direct relation between the intensity of Cube component and the amount of cold reduction.

Abstract: Texture evolution in pure Mg and Mg alloy AZ31 during deformation and annealing was investigated. The poor low temperature ductility can be attributed to both, insufficient shear systems and unfavorable deformation geometry. Static recrystallization was shown to proceed discontinuously despite little texture change. High temperature deformation was accompanied by dynamic recrystallization with similar texture development as during static recrystallization.

Abstract: 6111 Aluminium Alloy in the hot band state was cold rolled to 80% was then annealed at 450oC, 500oC and 540oC for recrystallization. The hot band was also solution heat treated, cold rolled and annealed to the same temperature to look at the difference in the recrystallization texture and precipitation states. It was found that the samples which were cold rolled and annealed without solution heat treatment gave Goss and P components after annealing. For the samples with solution heat treatment, the 450oC sample has a retained Cu type rolling texture while for the 500oC and 540oC the textures are quite random. The retained rolling texture found in the 450oC sample is due to the fact that it was partially recrystallized as the precipitates prevent complete recrystallization. The difference in the precipitation states during and after annealing of the samples with and without solution heat treatment affects the final recrystallization texture.

Abstract: In order to improve deep drawability of Al-Mg-Si alloy sheets for automotive body panel by texture control, the effects of Mn addition and warm rolling on recrystallization texture were investigated for rolled and T4 treated sheets and the r-value was related to overall texture through thickness. Recrystallization texture after T4 treatment varied significantly depending on alloy composition and rolling condition. Planar anisotropy of r-value could be predicted relatively exactly from recrystallization texture by the Taylor full constraints model for all specimens. Mn addition led to an increase of average r-value in both cold and warm rolled materials, while warm rolling resulted in a decrease of average r-value in spite of relatively high predicted r-values in the surface layer.

Abstract: The effect of warm and cold rolling parameters on the development of annealing textures was studied in two low carbon steels containing additions of chromium. Two warm rolling temperatures (640 and 700°C) were employed together with a reduction of 65%. The effects of an additional cold rolling reduction of 40% and of decreasing the heating rate during annealing were also studied. The ND fiber, <111>//ND, of the recrystallization texture was strengthened as the warm rolling temperature was decreased. However, all the warm rolled steels contained a retained RD fiber, <110>//RD. A noticeable improvement in both the continuity and intensity of the ND fiber was obtained when the sample was submitted to an additional 40% cold rolling reduction. The ND fiber was even more continuous and intense when a low heating rate was utilized, yielding r-values of 1.1 and 1.3 for the warm rolled and warm plus cold rolled samples, respectively.

Abstract: In order to demonstrate the effect of deformation temperature on texture formation in silver alloy sheet for superconducting types, the deformation and annealing textures of Ag-10 at% Pd alloy rolled at the temperatures from -1960C to 1600C and subsequently annealed were examined. A single Copper type texture with high intensity in ODFs has been realized in this study. Based on the experimental results, a metallurgical processing to get a sharp single orientation type texture in Ag-Pd alloy has been presented for manufacturing highly oriented superconducting substrate tapes.

Abstract: In order to obtain a sharply cube textured silver sheet as the substrate for high temperature superconductor (HTS) film with high Jc (critical current density), warm rolling combined with two step annealing treatment has been performed to clarify the perspective of texture formation in pure silver. Two kinds of starting material, which are silver ingots of commercial purity obtained by casting in air and vacuum, were used to examine the effect of oxygen on texture development. The main feature of warm rolling texture obtained in this study was a strong Brass {011}<211> component with minor S {123}<412> component, and in some cases, cube {001}<100> component or Copper {112}<111> component appeared also depending on the warm rolling procedures. Upon crystallization, {001}<100>, {124}<4,12,7> and {13,6,15}<365> orientations were formed as the dominant components in silver sheets and the relative amount of their orientation components depended on the concrete annealing conditions applied and on the oxygen content. A very sharp single-crystal like cube texture has been successfully realized in the specimen, which was cast in vacuum, warm rolled by 95 percent and subsequently annealed as 1500C×10 min-5000C×30 min in nitrogen. Finally, we discussed the technological basis on sharp cube texture formation in f.c.c. pure metals with low stacking fault energy.

Abstract: A novel X-ray diffraction method, allowing the position resolved imaging of a polycrystalline specimen using the diffracted radiation, was applied for in situ investigation of recrystallization of cold-rolled copper. A large area of the specimen could be observed simultaneously, yielding information about nucleation and growth of many individual crystallites. The recrystallization process showed a stochastic behavior which can be described by the model of self-organized criticality.

Abstract: The evolution of texture as a function of recrystallization has been characterized for hotrolled AA1050. Samples prepared from hot rolled sheet were annealed isothermally for sufficient time to allow complete recrystallization. The microstructural variation and texture evolution in the samples was observed by automatic indexing of Electron Back Scatter Diffraction (EBSD) patterns in a Scanning Electron Microscope (SEM). The spatial orientation variation within the deformed microstructure of nucleation, growth and orientations of recrystallized grains was examined. The orientation spread within grains was found to be a useful quantity for partitioning recrystallized and unrecrystallized regions. Also the effect of deformation texture on the evolution and growth of various recrystallization texture components was analyzed. The analysis is aimed at obtaining a correlation between the deformation microstructure, texture development and recrystallization kinetics in the hot-rolled condition. Preliminary results suggest only a weak correlation between the rate of recrystallization and the deformation texture component.

Abstract: Recrystallization of cold rolled {211}<011> single crystal of 3.5%Si-Fe were investigated by electron back-scattered pattern (EBSP) technique in order to clarify the formation of {h,1,1}<1/h, 1, 2> fiber in recrystallization texture of steel with high cold rolling reduction. In the cold rolled sample, there exist shearband like substructures characterized by the orientation fluctuation with single <011> axis whereas their orientations are almost kept to the original orientation {211}<011> which belongs to a-fiber (RD//<110> fiber). In the recovery stage, the orientation fluctuations are enhanced and include fluctuations with another <011> axis. That is the fluctuations in recovery stage are not characterized by rotation relationship with single <011> axis. The recrystallization texture includes {100}<012> and {411}<148> as major orientations in {h,1,1}<1/h, 1, 2> fiber. Furthermore, there exists clear orientation relationship characterized by multiple rotations with <011> axes between the recrystallization orientations and the original one. Actually, orientations characterized by rotational relationships with <211> (=[110]+[101]) axis and <111> (=[110]+[101]+[011]) were observed. These results suggest that recrystallization from a-fiber is occurred as a result of the final enhanced stage of the fluctuations characterized by multiple rotations with <011> axes.