Influence Of Processing Temperature Research Articles

Influence of Processing Temperature and Strain Rate on the Microstructure and Mechanical Properties of Magnesium Alloys Processed by Single-Pass Differential Speed Rolling

Magnesium-based alloys show significant promise for widespread applications owing to their lightweight nature and improved mechanical properties achieved through grain refinement via hot rolling. This investigation focuses on Mg-xAl-yCa-zMn (AXM alloys), pre-heated to temperatures of 350, 400, and 450 °C and processed via both single-pass differential speed rolling (DSR) and conventional rolling (CR). The key findings reveal the interplay between processing temperature, strain rate during single-pass rolling, and an innovative approach for incorporating varying amounts of Ca, influencing grain size, quantity of dynamic recrystallization (DRX) grains, and overall mechanical properties, including strength and ductility. A noteworthy observation is the positive correlation between an increase in the total reduction during hot rolling and a higher fraction of DRXed grains. This leads to a significant reduction in average grain size, diminishing from 60.3 ± 54.3 μm to 19.5 ± 14.2 μm at 40%, nearly a third the size of T4 grains (the initial homogenized microstructure of the AXM alloys). The resultant material strength experiences a doubling from an average of 125 ± 10.2 MPa (T4) to 260 ± 25.8 MPa (DSR rolled at 40%) for the AXM alloys with potential improvement in the ductility depending on rolling speed conditions. This study also aims to analyze the combination of rolling temperature, rolling speed, thickness reduction, speed difference and Ca content implemented across a wide range of temperatures and strain rates to provide a holistic approach to the processing parameters affecting the microstructure and mechanical properties of AXM alloys. Furthermore, this study provides a deeper understanding of DRX mechanisms, including continuous DRX (CDRX), discontinuous DRX (DDRX), and twinning induced DRX (TDRX), while each of these mechanisms plays a distinct role in the overall enhancement of formability and performance of magnesium alloys.

Mechanical properties of porous Si3N4–SiC composites fabricated at 1200 °C

Porous Si3N4–SiC composites are potentially very attractive for various advanced applications such as aerospace and solar thermal power plants. However, processing of these porous composites is difficult and expensive due to the requirement of very high temperatures. In the present work, porous Si3N4–SiC composites were fabricated at only 1200 °C using phosphoric acid both as a pore former and binder. Porous composites with a constant SiC content were fabricated using various H3PO4 content and the morphology and mechanical properties of the porous composites were systematically investigated. The addition of SiC particles resulted in significant improvement of stiffness, compressive strength, and flexural strength over monolithic porous Si3N4, and porous composites fabricated using 40 vol% H3PO4 yielded the best properties of longitudinal elastic constant >50 GPa, flexural strength >80 MPa, and compressive strength >180 MPa. The achieved mechanical properties have been discussed in light of the analytical micromechanical models for Young's modulus and minimum solid area theory. Finally, the influence of processing temperature on the evolution of porosity and crystalline phases has been systematically studied and the dependence of porous composites' stiffness on these parameters has been investigated in detail.

Hydrotreatment of Eucalyptus sawdust: The influence of process temperature and H2SO4 catalyst on hydrochar quality, combustion behavior and related emissions

Hydrothermal carbonization (HTC) presents a promising avenue for waste-to-energy conversion, owing to its cost-effectiveness, low emissions, and adaptability. This study employed HTC to convert Eucalyptus grandis sawdust residues into hydrochars (HC). HTC was conducted for 60 min in a high-pressure steel reactor within glycerin thermal bath equipment under different temperatures (150, 170, 190, and 220 °C) and reaction mediums (water and H2SO4 concentrations of 0.1 and 0.2 mol L–1). The resulting HC underwent thorough analysis, encompassing proximate, ultimate, and morphological assessments and investigations into combustion behavior and potential emissions. Moreover, a new indicator, the hydrotreatment severity index (HSI), is proposed to provide a standardized measure of hydrotreatment severity and property predictions. Higher temperatures and increased H2SO4 concentrations were found to reduce solid yield (ranging from 43.21 % to 90.72 %) and induce morphological changes, including an abundance of carbon microspheres, particularly at higher acid concentrations. These modifications substantially improved higher heating values (HHV), up to 34 % (HHV of 25.72 MJ kg−1 achieved at 220 °C with 0.2 mol L–1 H2SO4) compared to raw feedstock. Interestingly, the intermediate temperature of 190 °C contributed significantly, enhancing HHV by 33 %. All HTC processes greatly enhanced the combustion performance and ignitability of hydrochars. The most favorable reactivity (S = 7.61E7 %2 min−2 °C−3) was observed at 220 °C with 0.2 mol L–1 H2SO4, along with an estimated CO2 emissions of 2,058.46 kg per ton of hydrochar. These results underscore the efficacy of the simplified methodology and reactor system, emphasizing the critical roles of H2SO4 as catalyst and temperature in shaping the characteristics and performance of hydrochars from a representative Brazilian residue, Eucalyptus grandis.

Mechanisms and mechanical properties of high-temperature high-pressure sintered vanadium carbide ceramics

Vanadium carbide (VC) is extensively employed as a reinforcing agent in coating materials and a grain refiner in hard alloys, owing to its exceptional mechanical properties. A series of bulk VC ceramics were fabricated via high-temperature high-pressure sintering, followed by a comprehensive and systematic investigation of various properties of the sintered samples. The results revealed significant influences of processing temperature on the properties of sintered VC at 5.0 GPa. However, the exact nature of temperature dependence varied depending on the specific property. It was found that VC ceramics sintered at 1100 °C and 5.0 GPa exhibited the best overall performance, providing a relatively optimal temperature condition for synthesis. The Vickers hardness of the material reached an astonishing 43.2 GPa under a 9.8 N load, placing it within the category of superhard materials. However, the sintered sample exhibited a gradually lower hardness value of 30.4 GPa under a higher load of 29.4 N. Highly dense with a relative density of 99.8%, exhibiting near full density, the vanadium carbide ceramics possess an impressive Young's modulus of 544 GPa, indentation fracture resistance of 5.4 MPa m1/2, and an oxidation initiation temperature of 758 °C. This study offers practical guidance for the design of novel transition metal carbide superhard materials and provides valuable insights for the exploration of visualizing directions in the next generation of superhard materials.

Influence of processing temperature on production of red beetroot powder as a natural red colorant using foam-mat drying: Experimental and modeling study.

With high medicinal and nutritional value, red beetroot powder is utilized as a natural pigment and functional additive in various food industries. In this investigation, red beetroot powder was produced using foam-mat drying, and the effect of drying temperature on quality attributes was evaluated. Computer simulation was also performed to assess the impact of temperature on uniformity of moisture loss and temperature during drying. Temperature variations did not exert a significant impact on water solubility and total color difference of the powders. Images obtained from field emission scanning electron microscopy illustrated that with increasing temperature, wrinkling, cracking, and roughness of the powder particles reduced because of the formation of smooth and hard crusts on the particles' surface. Predicted moisture content values were in good agreement with measured data. The results of this study could be used to optimize foam-mat drying of red beetroot to produce functional powders with suitable physicochemical and microstructural characteristics.

The Influence of Processing Temperature on the Tensile Properties of Melt-Spun PLA Fibres and their Self-Reinforced Composites

The temperature during the consolidation of self-reinforced PLA composites has a significant effect on their mechanical properties. In the present work, the effect of the consolidation or processing temperature on the properties of melt-spun, highly oriented PLA fibres is experimentally studied through single fibre tests. It is shown that the Young’s modulus and strain to failure of PLA fibres increases with exposure to consolidation / processing temperature, and the strength decreases more drastically. Using these data and findings from earlier studies, it is demonstrated that the dependence of the tensile properties of self-reinforced PLA composites on the processing temperature can be directly predicted from the single PLA fiber properties as a function of the processing temperature. This prediction holds true provided that the tensile properties of both the PLA fibers and self-reinforced PLA composites are measured using the same cross-head speed or strain rate.

Role of processing temperature on microstructure, mechanical properties and corrosion behavior of fine grained AZ31 magnesium alloy produced by groove pressing

AbstractAZ31 magnesium alloy sheets were processed at 250 °C and 300 °C by groove pressing, a severe plastic deformation technique to achieve grain refinement. The influence of processing temperature on the evolution of microstructure, mechanical properties and corrosion behavior was studied. Groove pressing significantly reduced the grain size of the alloy from 46 μm to 6.5 μm at 250 °C processing temperature. With the higher processing temperature (300 °C), grain growth (11.4 μm) was observed for the alloy. Number of twins appeared in the groove pressed samples. Higher hardness and tensile strength were measured for the groove pressed samples processed at 250 °C without significant loss in the ductility as reflected from the % of elongation due to the grain refinement. Corrosion performance of the samples assessed by potentiodynamic polarization studies indicated increased corrosion resistance for both of the grove pressed samples. However, sample at 300 °C exhibited better corrosion resistance compared with the sample processed at 250 °C. This can be understood by considering the effect of higher processing temperature on reducing the crystal imperfections which alters the corrosion behavior.

The influence of processing temperature on the mechanical properties of recycled PET fibers

Study towards the recycling of PET waste has arisen in the last decades. One of the most widely used methods was the mechanical recycling process due to its simplicity and low cost of production. In this research, PET waste obtained from the disposable water gallon containers was used to produce recycled PET fibers for textile applications. The PET fibers were prepared using the extrusion technique by varying the processing temperatures, i.e., 200, 210, 220, 230, and 240°C. The diameter, FTIR analysis, XRD analysis, and mechanical properties of the PET fibers at various processing temperatures were studied. The results showed that the optimum processing temperature for preparing recycled PET fibers was 210°C with a diameter of 0.23 mm, a degree of crystallinity of 8.9%, a tensile strength of 70.4 MPa, and an elongation at break of 83.6%. In conclusion, PET waste shows a promising application to be processed as recycled PET fibers for textile applications.

Investigation on evolution of microstructure and mechanical properties of heat-treatable 6010-S aluminium alloy during gas-based hot sheet metal forming process

Modern hot sheet metal forming processes offer the opportunity, especially in the automotive sector, to meet current demands for ultra-lightweight design. Due to the increased formability at the high process temperatures, high-strength aluminium alloys are increasingly coming into the focus of the industry. However, the complex thermo-mechanical interactions within these processes can lead to undesirable microstructural changes that could have a negative impact on the final mechanical properties. The purpose of this work is therefore to investigate the microstructural evolution of age-hardenable EN AW 6010-S alloy in the course of a modern gas-based sheet metal forming process and to quantify its influence on the resulting mechanical T6 properties. For this purpose, two different components were first formed at laboratory scale and the areas of microstructural interest were identified. Metallographic examinations and EBSD measurements were performed to visualize the influence of process temperature and deformation on the microstructure. EDX analysis helped to identify non-metallic phases. In the next step, artificial aging of the components was performed to increase the mechanical properties. Tensile tests and hardness measurements showed that the deformation and temperature have no negative influence on the final mechanical properties of the alloy.

Influence of processing temperature on microhardness evolution, microstructure and superplastic behaviour in an Al–Mg alloy processed by high-pressure torsion

Experiments were conducted to assess the effect of processing temperature on the hardness evolution, microstructure and the flow properties of an annealed Al–3Mg alloy processed by high-pressure torsion (HPT) at either 300 or 450 K. The results demonstrate that HPT processing at room temperature (RT) leads to higher microhardness values with a more uniform hardness distribution in the Al alloy compared with processing at 450 K. After 10 HPT turns at RT, the microstructure displayed a more intense grain refinement, a higher dislocation density and smaller Al3Mg2 precipitates than after HPT at 450 K. Accordingly, the metal processed at RT showed enhanced strength at RT and consistently exhibited superplastic flow during deformation at 523 K, with tensile elongations of ∼530–650% for strain rates from 10−3 to 10−2s−1. Conversely, a maximum elongation of ∼110% was recorded at 523 K in the alloy processed by HPT at 450 K. This behaviour is attributed to an enhanced thermal stability in the metal processed at RT compared with HPT at 450 K where deformation at 523 K led to the onset of abnormal grain coarsening due to a more disperse distribution of grain sizes and the partial dissolution and coalescence of Al3Mg2 precipitates after HPT processing.

Toughening of linear low-density polyethylene/brominated polystyrene blend by styrene-ethylene/butylene-styrene elastomer

Brominated polystyrene (BPS) is blended with linear low-density polyethylene (LLDPE) to improve its fire retardancy for various applications such as wire and cable covering. To improve compatibility and mechanical properties, styrene-ethylene/butylene-styrene (SEBS) copolymer was added as a compatibilizer. The influence of processing temperature and SEBS elastomer on morphology, interfacial and mechanical properties has been investigated. It was found that melt blending at 230 °C with addition of SEBS elastomer can significantly reduce the BPS particle size to less than 0.5 μm by forming a core-shell structure that enhances the interfacial strength between BPS and LLDPE phases. Addition of 8 phr SEBS elastomer can increase the Izod impact strength at −37 °C by a factor of nearly three, compared to the non-compatibilized LLDPE/BPS system. Double-notch four-point bending (DN-4PB) test reveals that crazing and shear banding are two primary toughening mechanisms for the observed increase in the low temperature impact strength.

Production-Process Simulation and Life-Cycle Assessment of Metakaolin as Supplementary Cementitious Material

An environmental assessment of metakaolin as a supplementary cementitious material (SCM) through an integrated production-process-simulation and Life-Cycle-Assessment (LCA) approach is presented in this work. Initially, process simulation models were developed to reproduce the basic stages of the metakaolin production process. The effect of various operational parameters and scenarios, such as calcination temperature, moisture of raw material and associated drying, exhaust gas recirculation and the use of alternative-fuel combustion to provide kiln heat requirements, was evaluated. The resulting process heat-demand and CO2-emission computations were used as inputs in the LCA along with upstream literature data using a cradle-to-gate approach. LCA results focused on the most relevant environmental impact category of cement production, the Global Warming Potential (GWP (100)). The major findings showed a strong influence of process temperature and kaolin humidity on the lifecycle GWP, since both parameters affected not only the core-process heat demand but also the upstream impact related to fossil-fuel extraction, processing, transportation and distribution. Recirculating the exhaust provided a GWP reduction potential of up to 19%. In all examined production scenarios, metakaolin depicted a lower Global Warming Potential compared to clinker due to the avoidance of emissions related to limestone calcination. As regards the impact contribution of fuels, coal was responsible for higher onsite emissions and natural gas indicated higher upstream emissions. The GWP (100) could be further reduced when alternative waste fuels such as plastic waste, MSW (municipal solid waste) and tires were used. The LCA results have been cross-checked with previous literature reports, and the corresponding deviations are accordingly explained. In any case, the LCA results of different studies are rarely directly comparable due to the numerous assumptions required, which cannot be identically replicated.

Evaluation of Processing Conditions in the Performance of Purging Compounds for Polypropylene Injection Molding

Purging is a fundamental process in the injection molding sector, aiding in color transition, material shifts, and the removal of contaminants. The purging compounds can be classified according to physical or chemical mechanisms and are affected by processing parameters, such as temperature, pressure, or soaking period. Despite some studies on the effect of processing parameters in purging action, an analysis of the rheological behavior and physico-chemical changes is still required for a deeper understanding of this type of system. This study explored shear viscosity, activation energy behavior in the torque rheometer, injection molding process, and energy consumption for two polyolefin-based purging compounds: one on polypropylene (PP) and another on polyethylene (PE). The results showed that the PP-based compound is a highly viscous material with low thermal sensibility and low energy consumption. The PE-based chemical compound, which includes an expanding and scrubbing agent, presented higher thermal sensitivity. Lower purging times and specific energy consumption were observed for the mechanical purge regardless of the processing temperature in the injection molding machine. However, torque and specific total mechanical energy differed due to viscosity and possible filler particle agglomeration. These findings demonstrated the influence of processing temperature on rheology and performance. Nonetheless, further studies regarding pressure, soaking time, and rheological modeling are recommended.

Influence of processing temperature on plasmin activity and proteolysis in process streams from cold microfiltration of skim milk

Plasmin in process streams derived from microfiltration of skim milk can result in casein hydrolysis, potentially affecting the quality and functionality of ingredients produced. To determine whether partitioning of plasmin into permeates was impacted by processing temperature, cold microfiltration of skim milk was investigated at 4, 8 and 12 °C. Permeate generated at 4 °C had the highest plasmin activity (0.0185 AMC units mL−1). When plasmin activity was expressed relative to β-casein content, differences in the extent of dissociation of β-casein, at the different processing temperatures, did not influence plasmin activity in the resulting permeate streams. Throughout storage at 37 °C, all retentates exhibited extensive plasmin-mediated hydrolysis of β- and αS2-casein; αS1-casein to a lesser extent. Particle size measurements before and after plasmin-mediated hydrolysis of permeates indicated that the proteolysis products of β-casein, γ-caseins, retained the ability to self-associate on heating, with particle size increasing with increasing temperature.

Вплив температури обробки на структуроутворення Cr-Mo-V сталі

The main way to improve the quality characteristics of the steel is a properly selected heat treatment, the purpose of which is to create a structure that would meet the requirements of the manufacturer. The size of the austenite grain in the steel depends significantly on the heating temperature during heat treatment, which in turn affects the final structure of the steel and mechanical properties after treatment. The experimental chromium molybdenum vanadium steel 31CrMoV9 (EN 10085:2001) was heated to temperatures in the range of 850...1050°C and cooled in water and air. The structure formation of the Cr-Mo-V steel after heating to different temperatures, quenching and tempering, consists of tempered martensite (including residual austenite) and alloyed carbides, and after normalization - bainite and martensite with different ratios. As the normalization temperature increases, the total area occupied by martensite increases without changing its morphology. The increase in the heating temperature leads to an increase in the amount of martensite from 10% at 850°С to 50% at 1050°С, correspondingly, the microhardness of the steel increases, shown by research. With an increase in the tempering temperature, the average microhardness of steel decreases. The change in microhardness is probably associated with an increase in the amount of the residual austenite and the dissolution of alloyed carbides. Detected that with an increase in the heating temperature, the increase in the initial austenite grain led to the coarsening of martensite needles. The effect of the increasing the austenization temperature on the change in the structure of the Cr-Mo-V steel was shown during investigations. Detected that the temperature of the austenization affects the cooling rate. To obtain more detailed results of this effect, it is necessary to conduct additional investigations of the kinetics of the transformations in the Cr-Mo-V steel upon cooling from different temperatures. The obtained results make it possible to tentatively predict the final structure of the Cr-Mo-V steel after various modes of the heat treatment. Heating should be carried out at a temperature of 850ºС, which will additionally lead to resource saving to get a uniform structure in the Cr-Mo-V steel.

Influence of processing temperature on quality attributes of meat analogues fortified with l-cysteine

Meat analogues, mimicking the textural and sensorial properties of meat, could help consumers transition from animal-based foods to plant-based ones. However, improving the quality attributes of meat analogues, especially their textural properties is crucial to convincing more consumers to include these products in their diet. Here the effect of l-cysteine at a concentration of 0.2% in pea protein isolates (PPI) and wheat gluten (WG) blends was investigated according to the processing temperature (100, 110, 120, 130, 140, and 150 °C) in the high-temperature shear cell (HTSC). The macrostructure of fibers, as well as mechanical, microstructural, and quality attributes of products, were investigated to characterize the influence of l-cysteine on the PPI-WG blends processed at different temperatures. The results of this study showed that l-cysteine had different effects at different processing temperatures. It weakened the product structure and prevented fiber formation at processing temperatures of 100 and 110 °C. This effect was also observed at 140 and 150 °C but to a lesser extent. Conversely, at processing temperatures of 120 and 130 °C, the structure of the products with l-cysteine was stronger than those without l-cysteine, and they presented thicker fibers in visual pictures as well as the pictures obtained by scanning electron microscopy. It is concluded that l-cysteine can improve the textural properties of the meat analogues under precise processing temperatures. Thus, the potential of l-cysteine for improving the textural and quality attributes of meat analogues represents an important step towards the acceptance of a prevailing plant-based diet.

Gasificación de aserrín de pino: efecto de temperatura, tasa de oxígeno y vapor

The study of biomass gasification has gained great interest in recent decades, representing an attractive process for the production of energy and heat and the production of hydrogen and second-generation biofuels. The objective of this work is to characterize the composition of the producer gas, as well as its energy potential. Experiments are carried out in a fixed bed gasifier on a pilot plant scale, and bulk sawdust from pine wood is used as gasification raw material. The influence of process temperature (650-900 oC), oxygen rate (0.3-0.6) and steam / sawdust ratio on the gasification of pine sawdust are investigated. Results of this study show that the hydrogen content, both hydrogen and carbon conversion, the calorific value and the efficiency of the cold gas increase by increasing temperature and decreasing oxygen rate. The use of steam in the gasification process increases thermal efficiency and hydrogen content of the producer gas.

Rheological behavior of poly(propylene) reinforced with graphene nanoplatelets for injection molding

AbstractPoly(propylene) (PP)‐based graphene nanoplatelets (GnPs) nanocomposites are processed by a melt blending technique. To obtain more knowledge about the rheological behavior of nanocomposites for injection molding, the rheological characterization of nanocomposites is performed using a double capillary rheometer over a shear rate range from 10 to 6000 s−1. The influence of processing temperature (170, 180, and 190°C) is evaluated. To improve the interaction between PP and GnPs, maleic anhydride (MA) is applied as a compatibilizer. The viscosity master curves are fitted to the Cross‐WLF model. In relation to neat PP, the presence of GnPs promote a viscosity decrease. The nanocomposites containing MA exhibit a higher viscosity than the non‐compatibilized counterparts, suggesting adhesion improvement between PP and GnPs. In addition to the MA compatibilizer effect, the results show that its presence could act as a plasticizer/lubricant in the PP matrix. The morphology characterization of nanocomposites suggests that in addition to improving the adhesion between PP and GnPs, the MA presence also improved the GnPs dispersion in the PP matrix. The presence of GnPs and MA can affect the Newtonian behavior of the PP matrix. All studied samples reveal thermo‐rheological simplicity and pseudo‐plastic behavior.

Influence of process temperature and residence time on the manufacturing of amorphous solid dispersions in hot melt extrusion

The manufacturing of amorphous solid dispersions via hot melt extrusion is a topic of high interest in pharmaceutical development. By this technique, the drug is dissolved in the molten polymer above solubility temperature within the process time. In this study, an experimental framework is proposed determining the minimum required process temperature and the residence time using particularly low quantities of material. Drug/polymer mixtures in different ratios were processed in a micro-scale extruder while the process temperature and residence time were varied systematically. The phase situation was assessed by the turbidity of the final extrudate. Four different drug/polymer mixtures were investigated in three drug/polymer ratios. The minimum required process temperature was close to solubility temperature for each specific formulation. Moreover, an influence of residence time on the phase situation was found. About three minutes were required in order to dissolve the drug in the polymer at these process conditions.

Temperature influence on the triboelectric powder charging during dry coating of polypropylene with nanosilica particles

The influence of process temperature on the triboelectric charge during dry coating of cohesive polymer powders is investigated. The purpose of heating is to decrease the surface moisture of the powder, which results in an increase of electrical charge of the powder. The effect of the hydrophilicity of the SiO2 guest particles on the quality of the dry coating of PP host particles was investigated with respect to the integral charge of the dry coated powder. Furthermore, the flowability, crystallization behavior and degree of coverage (DOC) were investigated to determine the influence of the increased charge on these topics. Increased process temperature increases the electrical charge of the powder, which leads to a higher DOC with guest particles and, thus, drastically improved flowability compared to dry coating at ambient temperature. Furthermore, changes in the crystallization behavior of polypropylene are observed, due to more nuclei.