Deformation Texture Components Research Articles

Realstrukturbesonderheiten bei Warmumformung im Kaliber mit hoher Umformgeschwindigkeit

Microstructure changes occurring in the case of groove deformation have been studied on a ferritic and an austenitic steel (X 8 CrTi 17, X 8 CrNiTi 18 10). Groove deformation was carried out by a model process ― groove compression test ― and by pass-rolling (strain rate ranges from 1 to 4000 s −1 ). Corresponding microstructure changes are in good agreement for both processes. Recrystallization did not occur (T≤800 o C); dislocation density is high (10 10 -10 11 cm −2 ). There is a dominance of deformation texture components. Hot yield curves were calculated for groove compression test. Accompanying transmission electron microscopic investigations have proved a polygonized substructure in the ferritic and a dislocation cell wall structure in the austenitic steel

Inhomogeneous texture formation in high speed hot rolling of ferritic stainless steel.

Effects of inhomogeneous shear strain on the texture variation through the thickness of hot rolled ferritic stainless steel sheets are studied. The changes in texture with the progress of recrystallization are also investigated. Sheet specimens of AISI430 stainless steel are rolled at 1 000°C at a rolling speed of 20 m/s without lubrication and quenched into water at an interval of 3.5 to 250 ms after rolling. The redundant shear deformation by friction produces a severely sheared region beneath the surface, where a band of extremely fine recrystallized grains is formed when the strain exceeds a critical value.‹110› || ND axis density increases and ‹111› || ND axis density decreases with increasing shear strain. The deformation texture in the severely sheared region mainly consists of {110}‹001›, {110}‹112› and {112}‹111›. At the mid-thickness, it consists of ‹111› || ND and ‹100› || ND components. Only shear deformation is required for the formation of {110}‹001› texture. The sharpness of the preferred orientation decreases by the progress of recrystallization, but some components of deformation texture are retained throughout the thickness after recrystallization is completed.

The Mechanisms of Recrystallization in Cubic Metals with Particular Reference to Their Orientation-Dependence

AbstractAn analysis of the evolution of microstructure during deformation is made and the relationship between the microstructure and annealing texture development considered in detail. Although existing data are inadequate for a full assessment, it seems that all annealing texture components encountered in single-phase cubic metals can be explained in terms of one or other of three nucleation mechanisms. In situ subgrain-growth nucleation occurs for orientations within the stable-deformation texture, i.e. in regions of low lattice curvature. Transition band nuclei are of orientations remote from the stable deformation texture components in regions where slip rotations are divergent and nucleation at grain boundaries will provide orientations belonging to the principal spread about the deformation texture.The analysis applies for the most part to both fcc and bcc metals but there are some differences. One feature that is not common to both systems, the occurrence of the cube-texture in some fcc metals, is...

Development of Textures in Recrystallization

Conditions for the nucleation of recrystallized grains are briefly reviewed with emphasis placed on the orientation-dependent aspects. Distinction is drawn between nucleation sites within grains, at grain boundaries, and at transition bands. These sites are shown to have different orientation dependences. The role of second-phase particles is considered next, and their influence on the mechanisms and kinetics of recrystallization is related to the textures developed. Modification of annealing textures by soluble impurities is shown normally to result in retention of deformation texture components. Similar effects have been found to arise from long-range ordering, and may be attributed in both cases to a reduction in the ratio of growth rate to nucleation rate of recrystallized grains in the alloy. Conditions for growth selection of orientations have been re-examined in the light of new methods of texture description. The factors that influence texture development during grain growth after primary recrystallization are discussed briefly. Reference is made, where possible, to practical texture control in the manufacture of sheet metals and its influence during subsequent processing and use in service.

Effect of manganese on the annealing texture and strain ratio of low-carbon steels

A correlation between the plastic strain ratio, or γ value, and the manganese content of laboratory-prepared, low-carbon steels has been established. The\(\bar r\) value decreases consistently when manganese is increased from 0.05 to 0.56 pct. Excellent\(\bar r\) values are associated with manganese contents of 0.1 pct or less. The desirable (111) fiber texture in the low-manganese steels is obtained through recrystallization without appreciable grain growth. It is believed that a very low content of manganese in the steel, or its consequential effects in connection with nonmetallic impurities, may have influenced significantly the characteristics of recovery, hence the nucleation of recrystallized grains, of the various deformation texture components. X-ray line sharpening of several reflections during the early stages of annealing appears to be consistent with this interpretation.

Cross-rolling and annealing textures in high-purity iron

The deformation and annealing textures of cross-rolled high-purity iron specimens were determined by use of an X-ray Geiger counter spectrometer. The deformation texture was predominantly (100) [011], plus minor texture components of the (111) [110] or the (111) [112] type. In a partially recrystallized specimen, the minor deformation texture components were replaced by new orientations, while the (100) [011] main deformation texture was retained. A rather complex and widely scattered texture was developed in the completely recrystallized specimen. This recrystallization texture could be derived from the deformation texture components by rotations around (110) poles. The difference in the tendency for recrystallization among different deformation texture components may serve as an important factor in the formation of annealing textures.

Cube texture in copper

Copper single crystals of initial (358) [523] orientation, after being cold rolled to 98 pct reduction in thickness, were observed to retain essentially their original orientation. The operating mechanism previously suggested1 for this component of deformation texture in face-centered-cubic metals during recrystallization was experimentally observed to be valid to a certain extent.

Cherries versus fish for gulls : Clarence Cottam

Hot rolled Mg–1 wt% Nd alloy with a weak {0001}<112¯0> basal texture was subjected to plane strain compression (PSC) at room temperature. Compressive loads were imposed parallel to the in-plane (IPC) and through-thickness (TTC) directions of the rolled plate in order to engage different types of deformation twins. PSC was conducted up to 6% and 12%, and the deformed specimens were subsequently annealed at different elevated temperatures to investigate recovery and recrystallization in the formerly developed twins. Deformation and annealing textures and microstructures were characterized using X-ray diffraction, optical microscopy and electron backscatter diffraction techniques. Deformation under IPC and TTC displayed competitive activation of extension and contraction twinning, supplemented by homogenous dislocation slip. Deformation in IPC up to 6% witnessed equal activation of both aforementioned twinning modes that gave rise to soft and hard texture components. TTC up to 12% exhibited a less regular basal-type deformation texture, characterized by a large outspread in the rolling direction, and an asymmetrical splitting of the basal poles around the transverse direction by about −5° and +25°. Texture evolution during annealing was associated with general texture weakening, preserving the primary deformation texture components at relatively low annealing temperatures with no recrystallization (300 °C). Presence of strong impurity drag and particle pinning delayed the onset of recrystallization till 325 °C for TTC and 350 °C for IPC specimens, which took place preferably inside compression and double twins. Related recrystallized grains possessed a high Schmid factor (SF) for basal slip, and were larger and more prevalent on average than competing low SF grains related to extension twins or the matrix. Re-dissolution of precipitates at 450 °C triggered grain growth that led to strong evolution of orientations associated with compression and double twins as a result of a grain size advantage that emerges during recrystallization.