Connecting texture development to die design in extruded flat products

Optimierung der Eigenschaften von neuartigem Elektrobandstahl

As an important fabrication process, annealing treatment is conducted to eliminate distortion in magnesium alloy sheets. Second-phase particles can provide nucleation sites for recrystallization grains, and the basal texture is related to the recrystallization behavior. Three experimental Mg-2Zn-based magnesium alloy sheets were investigated by the salt bath annealing process. Combined with variations in hardness softening, evolution of microstructure and basal texture, the effect of second-phase particles on microstructure evolution was analyzed. The results showed that the significant influence of size and distribution of second-phase particles on static recrystallization in magnesium alloy sheets was exhibited, which lead to the formation of two stages in the annealing process, combined with static recovery behavior. Second phase particles with coarse size were beneficial to recrystallization grains’ nucleation and increased recrystallization behavior in the initial stage of annealing. Second-phase particles with fine size inhibited recrystallization behavior and weakened the softening of hardness. The basal texture was weakened by second phase particles at the stage of recrystallization nucleation. The change in basal texture at the stage of grain growth was related to the size of second-phase particles. The regulation of basal texture enhancement can be envisioned by modifying second-phase particles.

. Production efficiency as well as the reduction of energy consumption and waste are the main drivers for the improvement of large-scale production in chemical industry. In addition, the demand for new processes – these days especially related to the chemical energy conversion as basis for the Energiewende – are additional triggers for innovation. Catalysis, well recognized by the public e.g. in form of the 3-way automobile catalyst, plays an important role for about 90% of all processes in chemical industry. The development of new and improved catalysts is a challenge for chemists – as is the search for new structural materials for mechanical engineers. Due to the often-necessary noble and thus expensive metals (e.g. palladium) in many catalysts, structural and chemical function have been developed separately in the two communities. Recent progress in catalytically active materials allows replacing expensive noble metals in selected catalytic processes by significant cheaper elements [1]. This offers the new perspective to combine structural and chemical functionality by innovative materials. Within this area, intermetallic compounds with their peculiar combination of crystal and electronic structure [2], represent an interesting class of materials to address this vision as will be shown in the contribution.

Due to high local cooling rates and non-equilibrium directional solidification conditions, selective laser melting (SLM) processed metals exhibit microstructural and textural features significantly different from the conventionally processed ones. The evolution of crystallographic orientations in a maraging stainless steel (commercially known as stainless steel CX) sample fabricated by the SLM process was studied through experimental and modelling approaches Electron backscattering diffraction analysis showed that the dominant texture components in martensite and austenite phases are <111>|| building direction and <011>|| building direction, respectively. Texture simulation indicated that the formation of crystallographic orientations in the studied sample is the result of two consecutive phase transformations, from initially solidified delta ferrite phase with dominant cube fiber texture to austenite and austenite to martensite.

In an attempt to resolve questions recently raised regarding the principal high‐temperature slip systems in calcite, optical quality single crystals have been uniaxially compressed at 300–800°C and at a constant strain rate of ∼ 3×10−5 s−1. In addition, a single strain rate cycling test was performed at 650°C. The tests were all carried out with the compression direction parallel to , which lies at ∼30° to the c axis and makes angles of 52° and 23° with the poles to two rhombohedral (r) planes. Axial strains of 5–16% were achieved in the tests. The stress‐strain curves obtained showed three‐stage hardening behavior, while the strain rate cycling data showed flow stresses to be rather insensitive to strain rate with empirical power law fits yielding a conventional stress exponent of 22–30 at strains ≥ 5%. The active glide systems were identified by slip line analysis. Slip on r in the so‐called negative sense was found to be an important deformation mechanism across the entire range of temperatures investigated, while slip on a single f system in the negative sense became important at 650°C and above. The active f slip direction was of type, confirming the existence of a new set of f slip systems, namely, f , as opposed to the generally accepted f systems. In addition, clear evidence was found for significant slip on the basal (c) plane at temperatures above 600°C, probably in the 〈a〉 direction. By comparison with earlier data on crystals from the same batch, no evidence was found for significant strength asymmetry on the r and f slip systems in the positive and negative senses. Notably, the presently observed f and c sup systems have not been taken into account in previous modelling studies of plasticity and texture (i.e., crystallographic preferred orientation) development in calcite rocks, and r slip is usually taken as stronger in the positive than negative sense. Our results therefore imply a need for renewed modelling work on calcite, particularly regarding texture development at relatively high temperatures.

Slip behavior and its effect on rolling texture development in a dual-phase Mg–Li alloy

Crystallographic texture and microstructural changes in fusion welds of recrystallized Zry-4 rolled plates

The texture and anisotropy of magnesium–zinc–rare earth alloy sheets

Revealing the recrystallization behavior and mechanism of this new alloy is of great significance to subsequent research. In this study, the Ni-36.6W-15Co ternary medium heavy alloy was solution-treated at 1100–1200 °C for different lengths of time. The grain size change, microstructure and texture evolution as well as twin development during recrystallization annealing were analyzed using SEM, EBSD and TEM techniques. The study found that complete recrystallization occurs at 1150 °C/60 min. In addition, it takes a longer amount of time for complete recrystallization to occur at 1100 °C. The value of the activation energy Q1 of the studied alloys is 701 kJ/mol and the recrystallization process is relatively slow. By comparing the changes of microstructure and texture with superalloys, it is found that the recrystallization mechanism of the studied alloy is different from that of the superalloy. The development of annealing twins has a great influence on the recrystallization behavior and mechanism. The results show that the twin mechanism is considered as the dominant recrystallization mechanism of the studied alloy, although the formation and development of sub-grains appear in the early stage of recrystallization.

A critical test of twin-induced softening in a magnesium alloy extruded to a strain of 0.7 at room temperature

Texture evolution in Nd:YAG-laser welds of AZ31 magnesium alloy hot rolled sheets and its influence on mechanical properties

In this study, the cold rolling microstructure and static recrystallization mechanism of the high strength titanium alloy Ti-3.5Al-5Mo-6V-3Cr-2Sn-0.5Fe were systematically investigated. Results show that the cold rolling microstructure is mainly composed of the elongated deformed β grains containing micro-shear bands. After annealing at 815 °C for 2 min, the fine SRXed grains are observed, mainly concentrated in the micro-shear band, the grain boundary and the interior of the deformed grain. The sub-grain structure obtained by static recovery inside the deformed grain produces continuous SRX during the annealing treatment. Meanwhile, geometric and discontinued SRXed grains are also observed in the large deformed β grain and at the trigeminal grain boundaries, respectively. Many ultra-fine grains appear inside the micro-shear band, exhibiting a phenomenon of the micro-shear band assisting SRX. With the increase in the annealing holding time, the elongated β grains are significantly refined and the degree of recrystallization is continuously improved. In addition, the recrystallization behavior also results in a significant change in the fiber texture. With the extension of the annealing holding time, the rolling texture type evolves gradually, with the {111} &lt;112&gt; γ-fiber texture to weak α-fiber, γ-fiber, and Goss-fiber.

A model composite system comprised of tungsten fibres in a polycrystalline copper matrix has been used to examine the processes which control (i) matrix texture development, (ii) recrystallization behaviour in the matrix and (iii) the damage accumulation process. The composite was deformed in plane strain compression with the fibres parallel to the direction of zero strain (i.e. perpendicular to the loading axis). Experimental measurements were made of local and global texture development as well as metallographic observations of the pattern of recrystallization events and metallographic observations of damage events in the tungsten fibres or at the copper—tungsten interface. Physically based explanations are used to describe the results in terms of the local flow pattern in the matrix and the local distribution of stresses.

Deformation and texture development in CaIrO 3 post-perovskite phase up to 6 GPa and 1300 K

A new crystal plasticity scheme for explicit time integration codes to simulate deformation in 3D microstructures: Effects of strain path, strain rate and thermal softening on localized deformation in the aluminum alloy 5754 during simple shear