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Severe through-thickness texture inhomogeneity is apt to occur during hot-rolling of tungsten. This raises the intriguing notion of how is the inhomogeneity affected by stress-involved or heat-involved factors of the thermo-mechanical process. The texture development in the bulk and at the surface were investigated, and the main focus was on the role of grain boundaries on texture development. The deformed texture at the surface and in the bulk seems similar, but the recrystallized texture of them evolves in entirely different manner, hence, the through-thickness effect is considered to be unilaterally triggered by heat-involved factor, i.e., "annealing" rather than "straining". In the bulk, the recrystallized orientation basically retains the starting deformed γ-texture and θ-texture even if grain growth occurs. Meanwhile some subtle alternations (nucleation behaviors) show statistically a strong correlation with CSL relationships. At the surface, the deformed γ-texture is completely replaced by a prominent Goss texture ({110}〈001〉) at 1100 °C. The grain boundary plane distribution (GBPD) analysis demonstrates that the formation of Goss texture at the surface is controlled by low angle grain boundaries (LAGBs) and {112}〈111〉 or {100}〈110〉 oriented nucleation is controlled by Σ 3 CSL boundary. • Texture in bulk and surface of W and its crystallographic mechanism are analyzed. • Recrystallized texture retains the typical deformed γ-texture in the bulk. • Goss orientation at the surface basically replaces deformed γ-texture at low temperature. • LAGBs relate to formation of Goss and CSL GBs relate to the nucleation behavior. • Through-thickness textual non-uniformity can be solely triggered by annealing rather than straining. [ABSTRACT FROM AUTHOR]

In this work, a 6-pass hot-rolling process followed by air cooling is studied by means of a coupled multi-scale simulation approach. The finite element method (FEM) is utilized to obtain macroscale thermomechanical parameters including temperature and strain rate. The microstructure evolution during the recrystallization and austenite (γ) to ferrite (α) transformation is simulated by a mesoscale cellular automaton (CA) model. The solute drag effect is included in the CA model to take into account the influence of manganese on the γ/α interface migration. The driving force for α-phase nucleation and growth also involves the contribution of the deformation stored energy inherited from hot-rolling. The simulation renders a clear visualization of the evolving grain structure during a multi-pass hot-rolling process. The variations of the nonuniform, deformation-stored energy field and carbon concentration field are also reproduced. A detailed analysis demonstrates how the parameters, including strain rate, grain size, temperature, and inter-pass time, influence the different mechanisms of recrystallization. Grain refinement induced by recrystallization and the γ→α phase transformation is also quantified. The simulated final α-fraction and the average α-grain size agree reasonably well with the experimental microstructure. [ABSTRACT FROM AUTHOR]

Hot plastic working behavior and microstructure evolution were investigated during a production process of four medium-Mn steels, which differed in Mn (3 and 5%) and Nb contents. The production process started with casting, followed by hot forging, rough hot-rolling and concluded with final thermomechanical processing, which was performed to obtain multiphase bainite-based alloys with some fractions of retained austenite. The rough rolling was composed of four passes with total true strain of 0.99 and finishing rolling temperature of 850 °C, whereas thermomechanical processing contained five passes and total true strain of 0.95 at a finishing rolling temperature of 750 °C. During the process, the force parameters were recorded, which showed that the rolling forces for steels containing 3% Mn are higher compared to the 5% Mn alloys. There was no significant influence of Nb on the rolling parameters. The produced as-cast microstructures were composed of dendritic bainitic-martensitic phases. A positive effect of Nb micro-addition on a refinement of the as-cast structure was noticed. The thermomechanical processed steels showed fine multiphase microstructures with some fractions of retained austenite, the fraction of which depended on the Mn content in steel. The steels containing 3% Mn generated higher forces both during rough and thermomechanical rolling, which is related to slower recrystallization softening in these alloys compared to the steels containing 5% Mn. [ABSTRACT FROM AUTHOR]

Based on the research results, coefficients in constitutive equations, describing the kinetics of dynamic, meta-dynamic, and static recrystallization in high-carbon bainitic steel during hot deformation were determined. The developed mathematical model takes into account the dependence of the changing kinetics in the structural size of the preliminary austenite grains, the value of strain, strain rate, temperature, and time. Physical simulations were carried out on rectangular specimens. Compression tests with a flat state of deformation were carried out using a Gleeble 3800. Based on dilatometric studies, coefficients were determined in constitutive equations, describing the grain growth of the austenite of high-carbon bainite steel under isothermal annealing conditions. The aim of the research was to verify the developed mathematical models in semi-industrial conditions during the hot-rolling process of high-carbon bainite steel. Analysis of the semi-industrial studies of the hot-rolling and long-term annealing process confirmed the correctness of the predicted mathematical models describing the microstructure evolution. [ABSTRACT FROM AUTHOR]

Zinc alloys are proposed as suitable biodegradable materials due to an intermediate corrosion rate, non-toxicity, and good mechanical properties. The novel ternary Zn–Li–Cu alloy system is explored in this study as a potential biodegradable material for stent and other temporary medical device applications, utilizing pure Zn, Zn–Li, and Zn–Cu as control materials. After casting and hot-rolling, the chemistry, microstructure, mechanical properties, and immersion corrosion behavior of Zn-0.3Li-xCu (x = 2, 3.5, and 5 wt%) are investigated. The simulated Zn–Li–Cu ternary phase diagram compares well with experimental chemistry and phase fractions. Zn–Li–Cu alloys demonstrated excellent ultimate tensile strength (333–428 MPa) and hardness (125–134HV), with acceptable elongation (18–26%) compared to general stent design criteria and similar materials. In vitro corrosion rates of approximately 0.01 mm yr−1 were observed after 21 days of immersion in Hank's Balanced Salt Solution (HBSS), where depletion of metal ions is slowed by the formation of a dense corrosion product layer that partially breaks down after 100 days. The current study highlights that the novel Zn–Li–Cu alloys are promising candidates for medical device applications by exceeding stent design criteria. • Zn-0.3Li-xCu alloys evaluated for biomedical device applications. • Zn–Li–Cu phase diagram successfully simulated with Pandat software. • Ternary alloys have increased UTS, YS, and hardness, while elongation is decreased. • Evidence of change from ductile to brittle failure mechanism in ternary alloys. • Corrosion rate of ternary alloys decreased to 0.01 mm yr−1 after 21 days. [ABSTRACT FROM AUTHOR]

Supercabatteries combine the advantages of high power and energy density performances. However, the electrodes are always fabricated using high surface area materials and traditional slurry coating method containing the solvent mixing and drying processes, which are less controlled, energy-intensive, and environmentally unfriendly. Herein, we report a solvent-free method in pilot stage, combining a high-speed air blowing, hot-rolling, and hot overlying process. The carbon materials with high content of 40% are mixed in the LiFePO 4 -activated carbons cathode and Li 4 Ti 5 O 12 -activated carbons anode, respectively. The compact densities of the thick solvent-free electrodes (120 μm, one-side) are almost ~1.6 times of the values for the slurry coating electrodes. The solvent-free full cells show capacitive linear charge/discharge curves before the cell voltage plateaus. And these linear curves further mitigate the internal resistance drop at −40 °C using acetonitrile-assistant carbonate-based eutectic electrolytes. The full cell delivers high areal capacity of 1.4 mAh cm−2 and volume energy density of 95 Wh L−1, which is almost 2 times higher than that of the slurry coating full cell. Moreover, the supercabattery with acetonitrile-assistant electrolyte shows excellent cycling retention of 92% for over 5000 cycles due to the self-passivated solid electrolyte interface formation and stable fibrous polytetrafluoroethylene net-like binding structure. Image 1 • Li-ion supercabattery using LiFePO 4 - and Li 4 Ti 5 O 12 -based electrodes with 40% carbons. • Solvent-free electrodes combined air blowing, hot-rolling and overlying process. • Novel supercabattery shows high areal capacity, energy density and better cycling. • Contribution of capacitive controlled current can reach up to 68% at high rates. • Acetonitrile-assistant eutectic electrolytes ensured the −40 °C performance. [ABSTRACT FROM AUTHOR]

The effect of rolling temperature on the interfacial microstructure and mechanical properties of Ti/steel clad plates, fabricated by a newly designed method (cold spraying and hot-rolling), was studied. For this purpose, three rolling temperatures (i.e. 850, 950, 1050 °C) were selected to completely understand the bonding mechanism at Ti/steel interface. The type of interfacial compounds and thickness of the diffusion layers were found to be the main factors controlling the mechanical properties of the Ti/steel clad plates. Results showed that the Ti/steel clad plate rolled at 850 °C exhibited metallurgical bonding due to the formation of a 250 nm thick TiC diffusion layer at the interface, and resulted in the best elongation. In contrast, the sample rolled at 950 °C developed a 400 nm thick diffusion layer which was composed of TiC and FeTi compounds, leading to the best tensile strength. When the rolling temperature was increased to 1050 °C, the thickness of the diffusion layer (composed of coarse TiC and FeTi phases) was sharply increased to 4 μm, and the sample displayed poor tensile strength and elongation. [ABSTRACT FROM AUTHOR]

This paper shows a complete study about the characterization of the texture and the microstructure evolution of an industrial thermo-mechanical processing aiming to develop an advanced soft magnetic Fe–27%Co material with a sharp Goss texture. Thanks to its intrinsic magnetic properties, such an alloy should be able to get a place in the market of aircraft transportation transformers. It appears that the development of a highly Goss textured Fe–27%Co alloy could be achieved by optimizing the intensity of the Goss and rotated Cube texture during hot rolling using an adequate thermo-mechanical processing, namely finishing hot rolling in the ferritic phase. • Hot rolling conditions determine Goss development in Fe–27%Co alloy. • Hot rolling ending in the ferritic domain allows Goss texture optimization. • Hot rolling in the ferritic domain improves the magnetic induction. • Goss nuclei exist in shear bands of the {111}<112> grains at the cold-rolling state. • Low stored energy in Goss nuclei enhances their growth during annealing. [ABSTRACT FROM AUTHOR]

This research reports the processability and mechanical properties of silk resins prepared by hot-pressing followed by hot-rolling and then analyzes their thermal and structural properties. The results show that regenerated silk (RS) resins are better suited for hot-rolling than Eri and Bombyx mori silk resins (untreated silk). When hot-rolling at 160 °C with a 50% of reduction ratio, maximum bending strength and Young's modulus of RS resin reaches 192 MPa and 10.2 GPa, respectively, after pretreatment by immersion in 40 vol% ethanol, and 229 MPa and 12.5 GPa, respectively, after pretreatment by immersion in boiling water. Increased strength of the material is attributed to the increased content of aggregated strands and intramolecular linking of β sheets (attenuated total reflectance Fourier-transform infrared spectroscopy) and higher crystallinity (X-ray diffraction analysis). After hot-pressing and hot-rolling, RS resins have a stable decomposition temperature (297 °C). [ABSTRACT FROM AUTHOR]

Entry temperature estimation is a major concern for finishing mill set-up in hot strip mills. Variations in the incoming bar conditions, frequent product changes and measurement uncertainties may cause erroneous estimation, and hence, an incorrect mill set-up causing a faulty bar head-end. In earlier works, several varieties of neuro-fuzzy systems have been tested due to their adaptation capabilities. In order to test the combination of the simplicity offered by Takagi–Sugeno–Kang systems (also known as Sugeno systems) and the modeling power of type-2 fuzzy, in this work, hybrid-learning type-2 Sugeno fuzzy systems are evaluated and compared with the results presented earlier. Systems with both empirically and fuzzy c-means-generated rules as well as purely fuzzy systems and grey-box models are tested. Experimental data were collected from a real-life mill; datasets for rule-generation, training, and validation were randomly drawn. Two of the grey-box models presented here reach 100% of bars with 20 °C or less prediction error, while two of the purely fuzzy systems improved performance with respect to purely fuzzy systems presented elsewhere, however it was only a slight improvement. [ABSTRACT FROM AUTHOR]

The clad plate between ZrSnNb and FeCrAl alloy was fabricated through diffusion bonding at 850 °C for 5 h under mechanical pressure in an argon atmosphere, and subsequent hot rolling at 800 °C with 20, 37 and 50% rolling reduction. The annealing treatment on hot-rolled plate was carried out in vacuum at 800 °C for 480 h. Interface observation and phase analysis were performed by Electron Probe X-ray Micro-Analyzer (EPMA). The interface of clad plate was tightly bonded, and there were no cracks and pores. After 5 h solid-state diffusion bonding, the Zr 3 Fe phase formed at the diffusion layer with about ∼3 μm thickness. The αZrCr 2 , ZrFe 2 and Zr 3 Al intermediate phases formed at the interface in the 20% and 50% hot-rolled samples. While αZrCr 2 , Zr 3 Fe and Zr 3 Al phases formed at the interface in the 37% hot-rolled sample. There is no reasonable evidence temporarily to explain the formation of Zr 3 Fe phase at diffusion layer of 37% hot-rolled sample, and further study is necessary in near future. After annealing at 800 °C for 480 h, intermetllics formed and identified as αZrCr 2 , ZrFe 2 and Zr 3 Al and Zr 2 Fe. The average thickness of diffusion layer in FeCrAl/ZrSnNb clad plates with 20%, 37% and 50% rolling reduction was 6 μm, 9 μm and 11 μm, respectively. The results in this study could provide possible valuable guidance for fabricating multilayer fuel cladding materials for the application in nuclear reactor. Image 1 • The Zr 3 Fe phase formed at the diffusion layer after 5 h diffusion bonding. • αZrCr 2 , ZrFe 2 or Zr 3 Fe and Zr 3 Al phases formed at the interface of hot-rolled sheets. • The average thickness of 20%, 37% and 50% annealed samples was 6, 9 and 11 μm, respectively. • αZrCr 2 , ZrFe 2 and Zr 3 Al and Zr 2 Fe formed at the interface of annealed sheets. • Rolling deformation affected the diffusion distance during annealing. [ABSTRACT FROM AUTHOR]

• Oxide scales of ferritic and austenitic STS show various composition and microstructure according to Cr content. • Dense Cr 2 O 3 layer continuously formed along the interface in high Cr STS facilitates sticking failure. • Composite structure of Fe 3 O 4 , FeCr 2 O 4 and Fe x Ni y intermetallic compounds prevent sticking failure. The failure of oxide scales on ferritic stainless steels (STSs) has been known to cause an unexpected and severe sticking problem during the hot-rolling process. The oxide scale fragments formed during hot-rolling are stuck on the surfaces of the working roll, deteriorating the surfaces of both the roller and the rolled materials. In this study, we investigate the effects of the compositions and microstructures of thermally grown oxide scales on the degree of sticking during hot-rolling in three different kinds of commercial ferritic STSs and one austenitic STS. The STS samples are oxidized at around 1280 °C for 2 h, and the oxide scales formed on the STSs are identified by X-ray diffraction (XRD). Additionally, the cross-sectional microstructure and chemical compositions of the oxide scales on the STSs are examined by electron probe microanalysis (EPMA) and scanning electron microscopy (SEM), respectively. The oxide scales adjacent to the interfaces with the bulk STS are analyzed by high-resolution transmission electron microscopy (HR-TEM). The Gleeble test, which is a high-temperature (1250 °C) tensile test, is conducted to analyze the effects of the stress induced in the oxide scales during hot-rolling on the fracture of the scales. According to the microstructural analysis and mechanical test results, a brittle Cr 2 O 3 layer, where cracks are easily formed and propagate through the scale thickness under the stress induced by hot-rolling, is formed along the interfaces of STSs with high Cr contents. This effect increases the probability of sticking failure in high-Cr STSs. In contrast, scales with a composite-like structure of Fe- and Cr-oxides are formed on the surface of STSs containing low and medium levels of Cr. According to the Gleeble test results, the composite-like oxide scales show higher mechanical resistance to tensile stress than the Cr 2 O 3 layers in the high-Cr STSs. In addition, our microstructural analysis results reveal that Fe x Ni y intermetallic compounds are observed as a form of a composite-like structure inside the oxide scales in the austenitic STS and that this structure also delays crack propagation through the oxide scales and reduces the degree of sticking. [ABSTRACT FROM AUTHOR]

This work demonstrates an improvement in the mechanical performance of the high entropy alloy Fe 40.4 Ni 11.3 Mn 34.8 Al 7.5 Cr 6 containing 1.1 at. % carbon (CHEA) by hot-rolling followed by annealing at 1323 K. The microstructure was examined using scanning electron microscopy, electron backscatter diffraction, X-ray diffraction, and transmission electron microscopy. Room-temperature tensile tests were used to assess the alloy's mechanical properties. The presence of dense dislocation walls indicate that the alloy has not fully recrystallized and, moreover, the deformation substructure and the large fraction of Σ3 twin boundaries contribute to the high room temperature yield strength (~523 MPa). Despite the presence of substantial dislocation density, the annealed, hot-rolled CHEA displays an improvement in elongation to fracture (~33%) compared to the negligible ductility (<2%) observed for the alloy after it has been simply annealed. The present work shows that hot-rolling can produce good strength and ductility in the alloy while establishing the processing conditions necessary for the large-scale manufacture and utilization of its remarkable properties. • Hot-rolled and annealed Fe 40.4 Ni 11.3 Mn 34.8 Al 7.5 Cr 6 has a recrystallized fraction of 78% and average grain diameter of 80 μm. • The alloy demonstrates an excellent balance of room-temperature strength (~523 MPa) and elongation to fracture (~33%). • The enhanced mechanical properties show that hot-rolling is a suitable processing method for the CHEA. [ABSTRACT FROM AUTHOR]