Extrusion Parameters Research Articles

Impact of Extrusion Parameters on the Formation of Nε-(Carboxymethyl)lysine, Nε-(Carboxyethyl)lysine and Acrylamide in Plant-Based Meat Analogues.

To investigate the impact of extrusion parameters on the formation of Nε-(carboxymethyl)lysine (CML), Nε-(carboxyethyl)lysine (CEL) and acrylamide in plant-based meat analogues (PBMAs), the content changes and the correlations of compounds related to their formation were studied. The extrusion promoted CML, CEL and acrylamide formation, with more CEL being formed than CML. Variations in the moisture level and barrel temperature exerted a greater influence on the CML, CEL, acrylamide and α-dicarbonyl compounds than the screw speed and the feed rate. An increase in the moisture content led to a decrease in the CEL content, whereas it enhanced CML formation. The impact of moisture on acrylamide formation varied depending on whether low- or high-moisture extrusion was applied. Elevated temperatures promoted the accumulation of CEL, methylglyoxal and 2,3-butanedione while diminishing the accumulation of CML, acrylamide, glyoxal and 3-deoxyglucosone. CML and CEL were positively correlated with glyoxal and methylglyoxal, respectively. CEL and methylglyoxal were negatively correlated with protein and water content, whereas CML, glyoxal and 3-deoxyglucosone displayed positive correlations. In summary, higher moisture levels and feed rates and lower screw speeds and barrel temperatures are advantageous for producing PBMAs with lower CEL and total advanced glycation end-products contents, while lower or higher moisture contents, a lower feed rate and a higher barrel temperature are beneficial to reducing the acrylamide content.

Optimization of malted cowpea compositions and extrusion parameters for best quality Ethiopian emmer wheat-based snack food

Childhood malnutrition is a major concern in developing countries, particularly in Ethiopia. This study aims to address this problem by assessing the nutritional properties of snacks made from locally available raw materials. The study used a twin-screw extruder machine to study the effects of different processing conditions (barrel temperatures, feed moisture content, and cowpea/emmer wheat blending ratio) on the nutritional properties of extruded products. The results showed a highly significant effect of these processing variables on the nutritional properties of snacks. Increasing cowpea in the blend boosted the protein and fiber content of the snack products. Increasing the barrel temperature from 80 to 120 °C notably decreased the protein and fat levels in the snack. The optimization of the combined interactive effects on an extruded snack made from 19.83% cowpea and 80.17% emmer wheat, cooked at 120 °C barrel temperature with 22.04% feed moisture content, produced acceptable extruded snack items. The products developed with optimized parameters contained 16.68%, 1.55%, 2.50%, 70.95%, and 364.43 kcal/g for protein, fat, fiber, carbohydrate, and gross energy, respectively. The study concludes that blending Emmer wheat and cowpea in extruded snacks can provide high protein and gross energy. This suggests a locally viable solution for addressing protein-energy malnutrition in developing regions, particularly Ethiopia.

Fine grains, dispersed phases and strong crystal defect interactions inducing excellent strength-ductility synergy in powder sintered Cu–18Sn-0.3Ti alloy via hot extrusion and solution treatment

In order to prepare the Cu–18Sn-0.3Ti alloy with excellent mechanical properties to realize the favorable collaborative deformation of Cu–18Sn-0.3Ti alloy and Nb in the preparation process of Nb3Sn superconducting wires by bronze method, the hot extrusion process of the Cu–18Sn-0.3Ti alloy prepared by Direct Current assisted Hot Pressed sintering based on micron atomized spherical alloy powders was systematically investigated by the combination of experiments and finite element simulation in this work. The ultimate tensile strength, yield strength and elongation can reach 683.5 MPa, 414.3 MPa and 33.3 %, respectively, through the optimization of hot extrusion parameters and subsequent solution treatment. The results show that hot extrusion with high strain rate induced the formation of fine α grains and dispersed δ phases. Especially, strong dislocations-annealing twins (ATs) interaction occurred, which was manifested as the pile-up of dislocations at twin boundaries of ATs, slippage of dislocations in multiple directions inside ATs and storage of dislocations inside ATs. Meanwhile, the high strain rate induced the formation of deformation twins inside partial grains. The grain refinement of α matrix, formation of dispersed δ phases and strong interactions of crystal defects were the main reasons for the strength-ductility enhancement of hot extruded samples, and laid an excellent microstructure foundation for further improving the mechanical properties of alloy by subsequent solution treatment. The results not only describe a feasible method for simultaneously enhancing the strength and ductility of Cu–18Sn-0.3Ti alloy, but also provide a theoretical guidance for the strength-ductility enhancement of multicomponent alloys.

Recycling, thermophysical characterisation and assessment of low-density polythene waste as feedstock for 3D printing

Low-density polyethene (LDPE) is extensively used in single-end-use food packaging and contributes significantly to global waste plastic. This study addresses this challenge by introducing a sustainable approach to reclaim and valorise waste LDPE from milk packaging by converting them into 3D printing filaments. The process involves extruding shredded LDPE pouches into continuous filaments using a modified thermal extruder. The research comprehensively investigates the effects of two key extrusion parameters, nozzle temperature and screw speed, on the resulting filament's physical and mechanical properties. Characterisation efforts include dimensional analysis, morphological evaluation, chemical integrity assessment, thermal stability analysis, and tensile testing. The results show that filaments remain consistently close to 1.75 mm diameter, which is required by most commercial FDM 3D printers. The filaments are chemically intact, thermally stable, and have high toughness across the range of extrusion parameters. The results and a preliminary demonstration of 3D printing indicate that the LDPE waste can be effectively transformed into consistent filaments that have the potential for 3D printing. A carbon footprint assessment underscores the environmental benefits of this approach, showing substantial reductions in estimated CO2 emissions compared to conventional filament production methods. While challenges related to the quality of printed parts remain, the research opens avenues for optimizing 3D printing parameters and exploring multiple recycling cycles. This work represents a step towards sustainable plastic waste management and offers insights into transforming single-use plastic items into valuable resources.

Effect of different extrusion parameters on the microstructure and mechanical properties of Mg-4Sm-3Gd-2Yb-0.5Zr alloy

The effect of different extrusion parameters on the microstructure and mechanical properties of Mg-4Sm-3Gd-2Yb-0.5Zr (SGY2) alloy was investigated. It was observed that under different extrusion parameters, unDRXed grains of SGY2 alloy exhibited a pronounced basal plane texture, specifically <011¯0>//ED, while the texture of DRXed grains was relatively dispersed. Under the condition of 420 °C and an extrusion ratio of 9.4 (420 °C-ER9.4), the basal plane texture strength of unDRXed grains in SGY2 alloy was the highest. Furthermore, SGY2 alloy at different extrusion parameters exhibited recrystallization mechanisms mainly characterized by continuous dynamic recrystallization (CDRX), with some DRXed grains and deformed grains experiencing discontinuous dynamic recrystallization (DDRX). Additionally, at the 420 °C-ER9.4, the second phase particles in the as-extruded SGY2 alloy were smaller in size and exhibited a dispersed distribution. Under this condition, a significant amount of dislocation accumulation, dislocation bypassing, and dislocation tangling phenomena were observed in the SGY2 alloy. The primary deformation mechanism of unDRXed grains in the SGY2 alloy at the 420 °C-ER9.4 may involve prismatic plane 〈a〉, pyramidal plane 〈a〉, and pyramidal plane 〈c + a〉 slip, thereby activating a significant amount of dislocations. Compared to other extrusion conditions, this condition is more prone to activate non-basal plane slip. The as-extruded SGY2 alloy exhibited superior mechanical properties, with ultimate tensile strength (UTS) and yield strength (YS) of 332 MPa and 278 MPa, respectively. This is mainly attributed to the extremely fine grains, with many DRXed grains having grain sizes smaller than 1 µm, and higher density grain boundaries produced under this condition. Additionally, the unDRXed grains contain a high density of dislocations with small Schmid factor (SF), thus effectively inhibiting basal plane slip and strengthening the alloy to some extent. Similarly, the increased presence of second phase particles will also contribute to strengthening the alloy matrix through precipitation hardening.

Unveiling the impact of short fibre reinforcement and extrusion properties on microstructure of 3D printed polycarbonate composites

In the evolving realm of additive manufacturing, this study investigates the microstructural and mechanical implications of short fibre reinforcement within Polycarbonate (PC) composites fabricated via material extrusion (MEX). The research specifically examines the roles of extrusion temperature, extrusion multiplier and fibre content on void content and fibre alignment, with a focus on their influence on inter-bead strength and overall print quality. Through a combination of high-resolution micro-CT scanning and mechanical testing, the study reveals that an increase in the extrusion multiplier significantly enhances fibre-bridging up to 47 % and inter-bead adhesion up to 237 % depending on the fibre content. It also traces an optimal fibre content threshold that maximizes benefits of fibre bridging, thereby bolstering the mechanical properties of the material. The comprehensive analysis demonstrates that precise control over the extrusion parameters as well as filament quality are crucial for exploiting the full potential of fibre reinforcement in 3D printed structures. This research advances our understanding of MEX in fabricating short fibre-reinforced composites, offering novel insights for tailoring material properties to meet the demands of high-performance applications.

Advancing sustainable construction: Terracotta component development through extrusion-based 3d printing with local clay

This study examines the use of 3D printing technology in construction, specifically the use of local clay as the primary material for developing Terracotta components. The results demonstrate the feasibility and high print quality achievable with clay, establishing it as a viable material for 3D printing in construction. The analysis of physical properties, such as shrinkage, density, and water absorption, provides valuable insights. Thermal conductivity, also examined, contributes to a comprehensive understanding of material performance. The article identifies the optimal extrusion parameters for terracotta components. The evaluations show that the water absorption rates are within standards, and the density variation ranges from 1420 to 1466 kg/m³. Additionally, there is a direct correlation between thermal conductivity and density. The compressive strengths are diverse, ranging from 18 MPa to 33 MPa. While modulus of elasticity provides essential quantitative data for understanding the mechanical behavior of printed samples when subjected to various stresses. The internal structure significantly influences compression resistance in 3D printed bricks, emphasizing its importance in design. This research highlights the potential of 3D printing, specifically with clay, in sustainable construction. It encourages further exploration of its practical applications in the industry.

Mechanical and Thermal Properties of 3D-Printed Acrylonitrile Butadiene Styrene Reinforced with Rubberwood Fiber

An additive manufacturing (AM) has become very popular due to its simplicity in producing complicated products using just one process due to the layer-by-layer addition of material, which makes it possible for more complicated products to be created. The constraint of Fused Filament Fabrication (FFF) printed components with inadequate mechanical qualities has prevented AM from being widely adopted by numerous industries. The mechanical and thermal qualities of FFF printed components which is a pure polymer could be enhanced by reinforcing the wood fiber into the polymer. In this study, the twin-screw extruder was used to produce the wood plastic composites (WPCs) filaments, which were made with ABS (Acrylonitrile Butadiene Styrene) as the matrix material and 1-3wt% rubberwood fiber (RWF) for reinforcement. The effects of the extrusion parameter, such as the volume fraction of RWF and the temperature of the extrusion process, on the 3D-printed WPCs samples were investigated. The experimental results of 3D-printed WPC sample were found that the highest compressive strength value is 24.3 MPa, obtained from the rubberwood 1wt% at the extrusion temperature 218 °C whereas the pure ABS filaments obtaining from the commercial and extrusion process gave the values of 28.9 and 14.5 MPa, respectively. The highest value of tensile strength is 8.4 MPa with the rubberwood 2wt% and temperature 198 °C whereas the pure ABS filaments obtaining from the commercial and extrusion process gave the values of 10.9 and 7.4 MPa, respectively. The morphological analysis of the 3D-printed WPC sample was observed to exhibit an effect of printing process. The result showed that an increasing temperature of extrusion process increases both tensile and compressive strengths of the samples whereas an increasing amount of fiber increases the tensile strength but decreased the compressive strength. Analysis of variance demonstrated linear factor and 2-way interaction factor of the extrusion parameter influence on compression and tensile strength significantly. The rubberwood 2wt% and the temperature 218 °C was suggested to achieve the suitable condition for extrusion process for the 3D-printed WPC sample. In addition, the discussions were supported with the thermal properties achieved from Thermogravimetric analysis and Differential Scanning Calorimetry.

Investigating extrusion impact on functional, textural properties, morphological structure, and molecular interactions in hulless barley-based extruded snacks supplemented with mung bean.

The effect of varying extrusion conditions on the functional properties of hulless barley-mung bean (70:30) extruded snacks was investigated using response surface methodology with feed moisture (FM), barrel temperature (BT), and screw speed (SS) as process variables. Results revealed significant impacts on functional characteristics with varying extrusion conditions. Bulk density (BD) of extruded snacks ranged from 0.24 to 0.42 g/cm3, showing that lower FM and higher BT results in lower BD while it increased with increasing FM, SS, and BT. The expansion ratio (ER) of extruded snacks ranged between 2.03 and 2.33, showing BT and SS had a desirable positive effect, whereas increasing FM led to decreased ER. Increasing BT and SS depicted a negative effect on water absorption index, whereas FM showed positive effect, which ranged between 4.21 and 4.82 g/g. A positive effect on water solubility index was depicted by BT and SS, which ranges between 9.01% and 13.45%, as higher SS and BT led to starch degradation and increased solubility suggesting better digestibility. The hardness of extruded snacks ranged from 32.56 to 66.88 Newton (N), showing increasing FM increased hardness, whereas higher SS and BT resulted in lowering the hardness. Scanning electronic microscope (SEM) analysis revealed structural changes in extrudates in comparison with nonextruded flour, indicating starch gelatinization and pore formation affected by varying processing parameters. Shifts in absorption bands were observed in Fourier transform infrared spectroscopy (FT-IR), suggesting structural changes in starch and protein. Understanding the effects of extrusion parameters on product properties can help tailored production to meet consumers' preferences and the development of functional snacks with improved nutritional quality.

Optimization of Extrusion Parameters and Feed Composition for Enhanced Quality of Millet Extrudates

Extrudates prepared from cereal grains, such as corn, wheat, rice, and other starch-rich grains, are the second largest contributors to the global ready-to-eat snack market. These cereals contain optimal characteristics, like amount, type and particle size of starch/protein which are important for starch gelatinisation, viscosity and flow characteristics. These factors contribute to the rheology and organoleptic characteristics of the extrudates. In recent years, there has been a significant push in the utilization of the millets for development of extrusion products as they are ready-to-eat and considered as healthier. Major issues with 100% millet incorporation are dark colour, lower expansion, harder and denser extrudates and lower shelf life. In case of millets feed moisture (9-12%), barrel temperature (120-150°C) and screw (123-460 rpm) speed have favorable impact on expansion ratio and bulk density. Addition of starch containing cereals, legumes and hydrocolloids like sodium alginate and carboxymethylcellulose enhances expansion, lighten color and increases nutritional and health benefits. The aim of this review is to highlight the potential of extrusion technology for development of millet products, role of extrusion operating conditions and their effect on product parameters. The review also provides detailed insights about application of extrusion based 3-D printing, hot melt extrusion, hydrogel forming extrusion, centrifugal co-extrusion and extrusion-based encapsulation for the development of innovative millet based novel product development.

Stability of Dexamethasone during Hot-Melt Extrusion of Filaments based on Eudragit® RS, Ethyl Cellulose and Polyethylene Oxide

Hot-melt extrusion (HME) potentially coupled with 3D printing is a promising technique for the manufacturing of dosage forms such as drug-eluting implants which might even be individually adapted to patient-specific anatomy. However, these manufacturing methods involve the risk of thermal degradation of incorporated drugs during processing. In this work, the stability of the anti-inflammatory drug dexamethasone (DEX) was studied during HME using the polymers Eudragit® RS, ethyl cellulose and polyethylene oxide. The extrusion process was performed at different temperatures. Furthermore, the influence of accelerated screw speed, the addition of the plasticizers triethyl citrate and polyethylene glycol 6000 or the addition of the antioxidants butylated hydroxytoluene and tocopherol in two concentrations were studied. The DEX recovery was analyzed by a high performance liquid chromatography method suitable for the detection of thermal degradation products. The strongest impact on the drug stability was found for the processing temperature, which was found to reduce the DEX recovery to <20% for certain processing conditions. In addition, differences between tested polymers were observed, whereas the use of additives did not result in remarkable changes in drug stability. In conclusion, suitable extrusion parameters were identified for the processing of DEX with high drug recovery rates for the tested polymers. Moreover, the importance of a suitable analysis method for drug stability during HME that is influenced by several parameters was highlighted.

Simulation of taper heating and variable pressing rate to improve extrusion performance for high-strength aluminum alloys

The main process parameters of direct and indirect extrusion of aluminum alloys were studied using FE-modeling in this article. The subject of the study was the use of billets taper heating and variable pressing rate as compared to the standard extrusion conditions. Extrusion of AA2024 grade alloy and experimental Al-2%Cu-1.5%Mn-1%Mg-1%Zn alloy was considered. The flow stress-on-strain dependences within the 350 °C–450 °C range at strain rates of 0.1–10 s−1 were determined for the experimental alloy. Considering the time of billet transportation to the extrusion equipment, its optimum temperature gradient was determined to be 500 °C at the front end and 140 °C at the tail end. Direct extrusion of taper heated billets at the variable rate and elongation of 7 allowed increasing the process performance by 5.6 times (from 1.8 mm s−1 to an average of 10 mm s−1, in case uniformly heated billets are extruded at the constant rate). In case of pressing at high elongations (15 and 25), the performance increase was about 2 times. It was found that the use of taper heating, both in case of grade alloy and model alloy extrusion, in all the considered conditions, allows achieving a significant increase in performance. However, these results are considered to be most effective in case of direct extrusion at small elongation ratios.

Optimization of ECAP parameters of ZX30 alloy using feature engineering assisted machine learning and response surface approaches

The precise control of equal channel angular pressing (ECAP) deformation parameters is crucial for producing ultrafine grains in structural ZX30-Mg alloy biodegradable components. To address this challenge, this study aims to conduct a comprehensive analysis of the effects of various ECAP parameters on the microstructure, corrosion, and mechanical properties of ZX30 alloy. ZX30 was utilized through a maximum of 4 passes along routes A, Bc, and C, using die angles of 90ᵒ and 120ᵒ, by utilizing machine learning (ML), artificial neural networks (ANNW), response surface methodology (RSM), and simulated annealing (SA) techniques. Experimental investigations revealed the significance of the number of passes in reducing grain size by up to 1.9 µm, consequently enhancing both mechanical and corrosion resistance properties, notably in route Bc. The corrosion rate was enhanced by 97.6 % while the corrosion resistance was increased by 254 % compared to the as-annealed condition. RSM and simulated annealing optimization results closely aligned with experimental findings. The evaluation of each extrusion parameter revealed that the correlation coefficient, as determined by the optimized Gaussian Process Regression model, ranged from 94 % to 97 % for all evaluated responses, and near to unity via ANNW. The overall distribution of mechanical and corrosion measures showed a significant correlation with the number of passes, with route A, Bc, and die angle following closely behind. Interestingly, route Bc had the main impact on the yield strength, followed by the number of passes and die angle. Thus, the combination of statistically and mathematically selected techniques effectively promotes the attainment of optimal properties. Furthermore, the Simulated Annealing (SA) algorithm demonstrated its capability to provide optimal solutions for ECAP deformation parameters. This study presents a promising avenue for improving the accuracy of ECAP-induced structural optimization in ZX30 alloy.

Impact of extrusion temperature and moisture incorporation on nutrient digestibility in barramundi (Lates calcarifer) diet

This study aimed to evaluate the influence of extrusion temperature and moisture incorporation procedure on nutrient digestibility of diets fed to barramundi (Lates calcarifer). A single premix was processed under six contrasted extrusion processing conditions, with extruder barrel temperatures set at 100 °C and 110 °C, and liquid water either incorporated in the preconditioner, in the barrel, or in both. In a subsequent 33-day feeding trial, grow-out fish (758.3 ± 24.5 g) were fed the 6 diets and apparent digestibility coefficients (ADC) were assessed for 42 fatty acids, 17 amino acids, protein, lipids and energy. Digestibility of protein (92.3–93.7%), lipid (84.1–89.4%), and energy (69.4–75.2%) also remained unaffected by extrusion settings (P > 0.05). However, lower extrusion temperature and moisture incorporation in both preconditioner and barrel resulted in higher digestibility of poly-unsaturated fatty acids (PUFA), long-chain poly-unsaturated fatty acids (LC-PUFA), omega-3, omega-6 and 22:6 docosahexaenoic n-3 (DHA). Moreover, lower extrusion temperature significantly improved ADCs of essential amino acids, except lysine, histidine, and threonine (P < 0.05). The results showed no significant impact (P > 0.05) of the tested extrusion parameters on fish growth (TGC: 2.11 ± 0.17), feed intake, or feed conversion performance (FCR: 1.67 ± 0.13). The study unveils diverse responses to extrusion temperature and moisture levels regarding amino acid and fatty acid digestibility. These findings highlight the advantages of preconditioning during the extrusion process to enhance fatty acid digestibility.

Optimizing Screw Speed and Barrel Temperature for Textural and Nutritional Improvement of Soy-Based High-Moisture Extrudates.

Soy remains the legume protein of excellence for plant-based meat alternatives due to its fiber-forming potential. In this study, protein-rich powders from soy protein isolate (SPI), concentrate (SPC), and their mixture (SPM) were thoroughly characterized for their proximate composition, nutritional quality, and physicochemical properties to understand their structuring behavior during high-moisture extrusion. SPI presented higher degrees of protein denaturation and aggregation, least gelation concentration and lower essential amino acid contents. Thus, an SPI:SPC combination (1:9 ratio, 70% protein) was extruded at three different screw speeds (300, 350, and 400 rpm) and two temperature profiles (120 and 140 °C maximum temperature). The effects of the processing parameters on the extrudates were evaluated for their appearance (fibrousness), texture (TPA, cutting force, and anisotropy), color, protein structure (FTIR), and trypsin inhibitors. Higher temperatures resulted in softer and darker extrudates, with increased visual and instrumental anisotropy. Increasing screw speeds led to softer and lighter extrudates, without a clear fibrousness effect. β-sheet structures decreased and intermolecular aggregates (A1) increased after extrusion, especially at 140 °C, together with the formation of intramolecular aggregates (A2). Extrusion also significantly decreased the amount of trypsin inhibitors (>90%). This study demonstrates that extrusion parameters need to be carefully selected to achieve meat analogs with optimal textural and nutritional characteristics.

A brief review of machine learning-assisted Mg alloy design, processing, and property predictions

Owing to the hexagonal close-packed (HCP) crystal structure inherent in Mg alloys, strong basal texture can readily be induced through the processes of rolling or extrusion. The anisotropy of the texture of Mg alloys impacts their stamping and forming capabilities, limiting their use in certain applications. Microalloying and shear deformation are currently the most common methods of weakening the texture of Mg alloys. Many shearing processes have been extensively studied, and given that they require complex equipment and make it difficult to achieve mass production, major attention has turned to studying the design of microalloys. Traditional trial-and-error approaches for developing micro-alloying confront many challenges, including longer test cycles and increasing expenses. The rapid advancement of big data and artificial intelligence opens up a new channel for the efficient advancement of metallic materials, specifically the application of machine learning to aid in the design of Mg alloys. ML modeling can be used to find correlations between features and attributes in data, allowing for the development and design of high-performance Mg alloys. The article provides an extensive overview of machine learning applications in Mg alloys. These include the discovery of high-performance alloys, the selection of coating designs, the design of Mg matrix composites, the prediction of second phases, the microstructure modification, optimization of rolling or extrusion parameters, and the prediction of mechanical and corrosion properties. In conclusion, challenges and prospects for the rational design of alloys with machine learning support were discussed.

Revealing the microstructure, texture evolution and mechanical properties along the whole wall of Mg-Gd-Y-Zn-Zr cylinders by tailoring rotary backward extrusion parameters

In this article, industrial-specification Mg-Gd-Y-Zn-Zr alloy cylinder parts were successfully prepared by rotary backward extrusion process. The microstructure distribution and mechanical properties evolution of the whole wall of different cylinder parts were investigated, and the effects of different rotation speeds on the microstructure and properties were also revealed. The results showed that the strain of the cylinder wall increased significantly with rotation speed increased, thereby generating a higher driving force for the microstructure refinement. The transformation of the inner wall progressed from the deformed zone (bulk-shaped long period stacking ordered (LPSO) phases, coarse deformed grains, and fine recrystallized grains) to the strongly affected zone (particle-shaped LPSO phases and fine recrystallized grains), with the latter expanding as rotation speed increased. Furthermore, there was a gradient distribution of strain in the cylinder walls, with the strain gradient intensifying alongside rotation speed. The transformation of the strongly affected zone into the deformed region from the inner to the outer wall suggested a diminishing effect of rotation speed on LPSO phases fragmentation and grain refinement. Notably, increasing rotation speed rendered improvements in the strength and ductility of the cylinder wall. And mechanical properties also displayed a gradient decrease from the inner wall to the outer wall. This variation in mechanical properties of different regions was closely associated with the contributions of grain boundary strengthening, texture strengthening and second phase strengthening.

Effect of Ag content and extrusion on the microstructure and mechanical properties of Mg–Ag alloys

Recently, the Mg–Ag binary alloy has gained much attention as an antibacterial biomaterial. However, the relationships between the extrusion parameters, microstructure, and mechanical properties of Mg–Ag alloys haven't been clearly established. Therefore, in this paper, the effects of silver (Ag) content (0, 3, 6 wt%) and extrusion (as cast, extrusion ratio (ER) 7.1 and 72.2) on the microstructure and mechanical properties of Mg–Ag alloys are systematically investigated. The results indicate that for the Mg–Ag alloys with the same extrusion ratio, as the Ag increased from 0 to 3 wt%, Mg4Ag and Mg54Ag17 precipitated, leading to significant precipitation strengthening and an increase in the yield strength by over 137%. As the Ag increased to 6 wt%, the yield strength increased by only ∼20%, attributable to Ag promoting dynamic recrystallization, resulting in less grain refinement, a slower amount increase and a smaller size reduction of the precipitate. For the Mg–Ag alloys with the same Ag content, as the extrusion ratio increased to 7.1, the yield strength increased significantly by over 37%, since the grain boundary strengthening and precipitation strengthening were significantly enhanced as the grains were refined, a large number of precipitates appeared, and their sizes significantly reduced. When the extrusion ratio increased to 72.2, the yield strength increased by only ∼10%, due to the weakening of both grain boundary strengthening and precipitation strengthening as the recrystallization further improved, leading to an increase in grain sizes, the redissolution of precipitates, and a lesser reduction in their sizes.

Circular economy innovation: A deep investigation on 3D printing of industrial waste polypropylene and carbon fibre composites

Transforming waste polypropylene (PP) and waste carbon fibre into upcycled composite materials for additive manufacturing represents an ideal circular economy challenge. An optimized method for material extrusion and 3D printing was developed to overcome adhesion and warpage challenges during printing. The study explored the impact of varying waste carbon fibre weight fractions (0 wt%, 2 wt%, 5 wt%, 8 wt%, 15 wt%, and 25 wt%), firstly on the properties of filament and then on printability and mechanical properties of printed specimens. Optimized extrusion parameters yielded the successful fabrication of fibre-reinforced filaments. Micro-level assessment of the polymer revealed a decrease in mechanical properties due to thermal processes during filament making and 3D printing. Microstructural analysis, along with optical and scanning electron microscopy, provided insights into inter-bead voids, debonding, fibre dispersion, fracture modes, and filament/sample quality. Differential Scanning Calorimetry indicated slight matrix degradation during filament extrusion, leading to slightly reduced melting and crystallization temperatures.

To Standardise Parameters for Preparation of Extruded Feed Using Various Conventional and Non-Conventional Ingredients

The purpose of this research was to optimise extruder parameters for the preparation of floating fish diets with appropriate physicochemical qualities. The impact of temperature (90-120oC), moisture content (15%-30%), die diameter (2.0-4.0 mm) and pre-conditioning duration (15-30 m) on physical properties of the pellets such as bulk density, floatability, expansion ratio and water stability, were examined. Accordingly, four iso-nitrogenous (crude protein 35%) experimental diets were formulated for GIFT tilapia advance fry by replacing 50% of GNOC protein of the control diet (T0) by sunflower oilcake (SFOC) (T1), by linseed oilcake (LSOC) (T2) and by fish based silage (T3) protein. The pellets extruded using a combination of 120 oC extruder barrel temperature, 25% moisture content of feed mix, 2.0 mm die diameter and 30 minute of pre-conditioning duration gave most required pellet floatability (90-100%), expansion ratio (1.43-1.61), water stability (95-99%) and bulk density (0.8 - 0.9 g/cm3) for T1 and T2. However, fish silage when incorporated in the feed mix, it affected negatively in all the physical characteristics of a floating feed and resulted in higher bulk density and lower floatability, expansion ratio and also water stability.