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This study aimed to investigate the influence of extrusion temperature (ranging from 330 to 370 °C) on the microstructure, mechanical properties, and corrosion resistance of the Mg-2.0Zn-0.4Mn-4.0Al alloy. The findings reveal that dynamic recrystallization (DRX) occurs in all the as-cast Mg alloys, particularly noticeable at 350 °C. Lower extrusion temperatures result in uncomplete DRX, and insufficient dissolution and rearrangement of as-cast second phase particles, while higher temperatures induce significant grain growth of recrystallized grain. Consequently, due to finer and more homogenous recrystallized grains and the more evenly distributed second phase Mg2(Zn, Al)11 and Mg17Al12, the as-extruded Mg alloy at 350 °C exhibits superior mechanical properties and corrosion resistance, compared with all other as-extruded and as-cast counterparts. The results demonstrated that this Mg-2.0Zn-0.4Mn-4.0Al processed by casting and following hot extrusion at an appropriate temperature can be a potential candidate for new high-performance and cost-effective non-RE Mg alloys. [ABSTRACT FROM AUTHOR]

The microstructure and mechanical properties of recycled AA6063 aluminum alloy rods fabricated by hot extrusion of forging compacts formed by upsetting compacts of small AA6063 aluminum alloy pieces with different Fe contents before and after T6 heat treatment were studied. In the as-extruded state and with the higher extrusion ratio of 25:1, the microstructure consists of fully recrystallized grains, but the high iron content regions exhibit clearly finer equiaxed grains due to the stronger grain boundary pinning and nucleation effects of a higher number density of Fe-rich phase particles. Increasing the extrusion ratio increases both the strength and ductility of the as-extruded material. The reason is that increasing extrusion ratio enhances the bonding strength of the prior boundaries between the strips formed by deformation of the small pieces. In the T6 heat-treated state, increasing the extrusion ratio from 9:1 to 25:1 clearly increases the fraction of fine and equiaxed grains. The enhancement of the bonding strength and the refinement of the microstructure with the increase of extrusion ratio cause the yield strength and ultimate tensile strength to increase from 174 and 221 MPa to 213 and 237 MPa, respectively, and the elongation to fracture to decrease from 22.1 to 15.4%. Solid-state recycled samples all exhibit a ductile fracture behavior despite formation of microcracks at the prior boundaries. [ABSTRACT FROM AUTHOR]

This article presents the results of the modeling of the behavior of the titanium alloy Ti-3Al‑2.5V at the initial stage of extrusion of a tube billet. The influence of the gaps between the surfaces of the tool and the billet on the nature of its shape change and the strain state is discussed. In particular, the most deformed tube parts of the maximum (by modulus) strain tensor values are identified. The dependence of the Ti-3Al‑2.5V alloy tube extrusion force on the stroke of the pressure pad is calculated. The results of the calculation of the maximum forces and the forces at the steady-state stage are in good agreement with the data obtained under an industrial experiment. Horizontal extrusion leads to an asymmetry in the location of the deformation fields relative to the extrusion axis. Accordingly, an asymmetric distribution of properties arises in the extruded tube, which is experimentally confirmed using hardness measurements. Correspondence is established between the simulation data on the heterogeneity of the strain distribution over the wall thickness of the hot-pressed tube made of titanium alloy Ti-3Al‑2.5V, considering the pressing-out, with the results of micro- and X‑ray structural studies of the tube semifinished product obtained. [ABSTRACT FROM AUTHOR]

Aiming to achieve silicon nitride (Si 3 N 4) ceramics with high hardness and high toughness, one-dimensional textured Si 3 N 4 -based ceramics, with and without 0.5 vol% ZrB 2 additive, were prepared using spark plasma sintering combined with hot extrusion at temperatures of 1600 °C and 1800 °C. One-dimensional texture (f I = 0.89) was achieved at a hot extrusion temperature of 1600 °C for the Si 3 N 4 ceramic with the introduction of 0.5 vol% ZrB 2. The fracture toughness (7.49 ± 0.47 MPa m1/2) closely approached that of the Si 3 N 4 sample processed at the hot extrusion temperature of 1800 °C (7.95 ± 0.27 MPa m1/2), while the hardness (18.55 ± 0.18 GPa) was significantly higher than that of the Si 3 N 4 sample processed at a hot extrusion temperature of 1800 °C (16.48 ± 0.20 GPa). It was demonstrated that one-dimensional textured Si 3 N 4 -based ceramics with high hardness and toughness can be prepared by the introduction of ZrB 2 combined with low temperature hot extrusion. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) alloy is expected to be the promising medical implant material because of its similar strength and Young's modulus to human bone, good biocompatibility and biodegradability. In the present study, as-cast Mg-9.1Y-1.8Zn (WZ92) alloy was homogenized first and then hot extruded to regulate its mechanical and corrosion properties. The as-cast alloy composes of α-Mg matrix, Mg24Y5 eutectic phase and interdendritic 18R-long period stacking ordered (LPSO) phase, in which the continuous block- or rod-like 18R-LPSO phase can act as corrosion barrier to prevent the corrosion penetration. After heat treatment, the precipitation of intragranular fine lamellar 14 H-LPSO phase not only reduces the ductility of the alloy, but also provides channels for corrosion intrusion, thus severe corrosion pits are formed. First-principles calculation reveals that the 14 H-LPSO phase is more likely adsorbed with Cl atom, and chemical bonds are formed in the 14 H-LPSO/Cl interface, which results in the worst corrosion resistance of the homogenized alloy. Further extrusion improves the yield strength and ductility (266.7 MPa and 6.8% respectively) of the alloy significantly through fine-grain strengthening, particle dispersion strengthening and kink band strengthening. Meanwhile, the corrosion resistance of the extruded alloy is enhanced through the corrosion barrier effect of long strip LPSO phase, stable product film protection as well as the formation of uniform corrosion mode. This study proves that hot extrusion is an effective method to synergistically improve the mechanical properties and corrosion resistance of WZ alloys, which can provide a favorable reference for the preparation of high-performance medical Mg alloys. [ABSTRACT FROM AUTHOR]

This paper investigates the microstructure, texture, and mechanical properties of the Mg-4Zn-1Mn-0.5Ca alloy subjected to hot extrusion under varying conditions of temperature (260 °C, 300 °C, 340 °C) and extrusion speed (0.01 mm/s, 0.1 mm/s, 1 mm/s). The primary objective is to determine the optimal extrusion parameters within the selected experimental range for achieving superior mechanical properties. The results indicate that, when extruded at a constant speed of 0.1 mm/s, the alloy exhibits optimal performance at 340 °C, with a yield strength of 202 MPa, ultimate tensile strength (UTS) of 306 MPa, and elongation at fracture of 18.9%. A decrease in extrusion temperature leads to an increase in yield strength but a reduction in ductility. Specifically, the UTS reaches its peak at 342 MPa at 300 °C, while it drops slightly to 329 MPa at 260 °C. The final results show that the comprehensive mechanical properties of the Mg-4Zn-1Mn-0.5Ca alloy obtained by hot extrusion treatment with an extrusion temperature of 300 °C and extrusion speed of 0.1 mm/s are the best and can effectively improve the mechanical properties of the alloy and provide a good choice for the preparation of other biodegradable magnesium alloy products. [ABSTRACT FROM AUTHOR]

The microstructure, texture, and mechanical properties of as-extruded and cold-rolled Mg–8Li–3Al–2Zn-1Gd-0.2Zr (LAZ832-1Gd-0.2Zr) alloys were investigated with the aim of strengthening the alloy by combining hot extrusion and cold rolling. Cold rolling does not change the phase composition of as-extruded LAZ832-1Gd-0.2Zr alloy, but introduces a larger number of dislocations and twins into alloy matrix. Cold rolling leads to the weakening of the original {0001} basal and {112‾0}-{011‾0} prismatic textures in α-Mg matrix, as well as the α and γ fiber textures in β-Li matrix. But new slip systems that are favorable for cold rolling are activated, resulting in the formation of {033‾8} pyramidal and new prismatic ({112‾0}⟨101‾4⟩ and {101‾0}⟨21‾1‾10⟩) texture components. Cold rolling further strengthens LAZ832-1Gd-0.2Zr alloy on the basis of hot extrusion, mainly through work hardening effect caused by introducing a large number of dislocations into α-Mg matrix. When the rolling reduction is 45%, the yield strength and tensile strength of LAZ832-1Gd-0.2Zr alloy are increased to 269.8 ± 4.0 and 308.6 ± 4.1 MPa, respectively, and the elongation is higher than 15%.

In this paper, (0.2–1 wt%) Yb was added to improve the tensile properties and high-cycle fatigue behavior of the as-cast and as-extruded Mg-10Li-5Zn-0.5Er alloys. It is found that Yb mainly affects the mechanical properties of the alloy by changing the grain size, type and morphology of the second phases. Yb mainly exists in the formation of Mg2Yb and Mg-Zn-Yb phases in the metallographic structure. With the addition of Yb, the grains are refined and these Yb-containing phases replace the large-sized MgLiZn phase to be enriched at the grain boundaries. While the addition of excess Yb reduces the number of small-sized MgLiZn phases in the grain, thus reducing the alloys’ mechanical performance. After extrusion, the small-sized MgLiZn phase is refined and the number increases, which effectively improves the tensile and fatigue strength of the alloy. The fatigue strength is mainly affected by the number and morphology of the second phase, positively correlated with the strength. Balanced in grain size and number and size of second phases, the extruded alloy with 0.2Yb added exhibits excellent mechanical properties with the yield strength, ultimate tensile strength and elongation of 292 MPa, 303 MPa and 11.7%, and an fatigue strength of 130 MPa.

Artificial intelligence methods, especially artificial neural networks (ANNs), have increasingly been utilized for the mathematical description of physical phenomena in (metallic) material processing. Traditional methods often fall short in explaining the complex, real-world data observed in production. While ANN models, typically functioning as "black boxes", improve production efficiency, a deeper understanding of the phenomena, akin to that provided by explicit mathematical formulas, could enhance this efficiency further. This article proposes a general framework that leverages ANNs (i.e., Conditional Average Estimator—CAE) to explain predicted results alongside their graphical presentation, marking a significant improvement over previous approaches and those relying on expert assessments. Unlike existing Explainable AI (XAI) methods, the proposed framework mimics the standard scientific methodology, utilizing minimal parameters for the mathematical representation of physical phenomena and their derivatives. Additionally, it analyzes the reliability and accuracy of the predictions using well-known statistical metrics, transitioning from deterministic to probabilistic descriptions for better handling of real-world phenomena. The proposed approach addresses both aleatory and epistemic uncertainties inherent in the data. The concept is demonstrated through the hot extrusion of aluminum alloy 6082, where CAE ANN models and predicts key parameters, and ChatGPT explains the results, enabling researchers and/or engineers to better understand the phenomena and outcomes obtained by ANNs. [ABSTRACT FROM AUTHOR]

• The effect of Yb on the microstructure and mechanical properties of Mg-Li-Zn alloy is proved. • A Mg-Li alloy with a fatigue strength of 130 MPa is developed. • The small-sized MgLiZn phase in the Mg-Li-Zn alloy has been observed. The transformation law of small-sized MgLiZn phase with the Yb content and hot extrusion treatment and its influence mechanism on the microstructure and mechanical properties have been clarified. In this paper, (0.2–1 wt%) Yb was added to improve the tensile properties and high-cycle fatigue behavior of the as-cast and as-extruded Mg-10Li-5Zn-0.5Er alloys. It is found that Yb mainly affects the mechanical properties of the alloy by changing the grain size, type and morphology of the second phases. Yb mainly exists in the formation of Mg 2 Yb and Mg-Zn-Yb phases in the metallographic structure. With the addition of Yb, the grains are refined and these Yb-containing phases replace the large-sized MgLiZn phase to be enriched at the grain boundaries. While the addition of excess Yb reduces the number of small-sized MgLiZn phases in the grain, thus reducing the alloys' mechanical performance. After extrusion, the small-sized MgLiZn phase is refined and the number increases, which effectively improves the tensile and fatigue strength of the alloy. The fatigue strength is mainly affected by the number and morphology of the second phase, positively correlated with the strength. Balanced in grain size and number and size of second phases, the extruded alloy with 0.2Yb added exhibits excellent mechanical properties with the yield strength, ultimate tensile strength and elongation of 292 MPa, 303 MPa and 11.7%, and an fatigue strength of 130 MPa. [ABSTRACT FROM AUTHOR]

This study investigates the impact of varying extrusion ratios on the microstructure and mechanical properties of AlSiCuFeMnYb alloy. Following hot extrusion, significant enhancements are observed in the microstructure of the cast rare earth aluminium alloy. Within the cross-sectional microstructure, the α-Al phase is reduced in size, and its dendritic morphology is eliminated. The morphology of the eutectic Si phase transitions from long strips to short rods, fine fibres, or granular forms. Similarly, the Fe-rich phase changes from a coarse skeletal and flat noodle shape to small strips and short skeletal forms resembling Chinese characters. The CuAl2 phase evolves from large blocks to smaller blocks and granular forms, while the Yb (Ytterbium)-rich rare earth phase shifts from large blocks to smaller, more uniformly distributed blocks. In the longitudinal section, the structure aligns into strips along the extrusion direction, with the spacing between these strips decreasing as the extrusion ratio increases. At an extrusion ratio of 22.56, the alloy demonstrates superior mechanical properties with a tensile strength of 325.50 MPa, a yield strength of 254.44 MPa, a hardness of 143.90 HV, and an elongation of 15.47%. These represent improvements of 27.8%, 36.5%, 38.9%, and 236.4%, respectively, compared with the as-cast rare earth alloy. In addition, the fracture surface of the extruded rare earth alloy exhibits obvious ductile fracture characteristics. Additionally, the alloy undergoes dynamic recrystallisation and dislocation entanglement during hot extrusion. The emergence of a twinned Si phase and a dynamically precipitated nanoscale CuAl2 phase are critical for enhancing deformation strengthening, modification strengthening, and dynamic precipitation strengthening of the extruded alloys. [ABSTRACT FROM AUTHOR]

In this study, composite materials with Al6061 alloy matrix and B4C particles reinforcement were produced by hot extrusion process. Fabricated composites were examined for the mechanical and machinability attributes. Al6061 alloy powders (<100 µm) and B4C particles (<10 µm) were mixed with the different weight fraction of B4C (3%, 6%, and 9% by weight) of and then cold pressed under 200 MPa pressure. The cold pressed powder metal block was extruded hot after preheating at 550°C for 1 h. Further, the composites were subjected to T6 aging heat treatment after hot extrusion. Microstructure, density, hardness, tensile strength, and wear properties were examined. The effects of cutting speed and cutting force on the machinability were also investigated. In addition, surface roughness and chips formation were examined. High density (99.6%) values were achieved with the extrusion process. With increasing B4C particles ratio, the hardness and tensile values were increased which was substantiated by the fracture morphology of the tensile specimens. It has been observed that tool smearing was high in the machining of the low-reinforced (3% B4C) composite. The highest cutting force was measured as 236 N at a feed rate of 0.27 mm/rev and a cutting speed of 250 m/min. It has also been observed that the average surface roughness decreased with increasing cutting speed and it increased with increasing feed rate. [ABSTRACT FROM AUTHOR]

The microstructure and mechanical properties of recycled AA6063 aluminum alloy rods fabricated by hot extrusion of forging compacts formed by upsetting compacts of small AA6063 aluminum alloy pieces with different Fe contents before and after T6 heat treatment were studied. In the as-extruded state and with the higher extrusion ratio of 25:1, the microstructure consists of fully recrystallized grains, but the high iron content regions exhibit clearly finer equiaxed grains due to the stronger grain boundary pinning and nucleation effects of a higher number density of Fe-rich phase particles. Increasing the extrusion ratio increases both the strength and ductility of the as-extruded material. The reason is that increasing extrusion ratio enhances the bonding strength of the prior boundaries between the strips formed by deformation of the small pieces. In the T6 heat-treated state, increasing the extrusion ratio from 9:1 to 25:1 clearly increases the fraction of fine and equiaxed grains. The enhancement of the bonding strength and the refinement of the microstructure with the increase of extrusion ratio cause the yield strength and ultimate tensile strength to increase from 174 and 221 MPa to 213 and 237 MPa, respectively, and the elongation to fracture to decrease from 22.1 to 15.4%. Solid-state recycled samples all exhibit a ductile fracture behavior despite formation of microcracks at the prior boundaries.

In this investigation, the effects of different annealing temperatures (180, 200, 220, 240, 260, and 280 °C) on the microstructure evolution and properties of an extruded Mg–2.0Zn–1.0Y–0.5Zr (wt%) magnesium alloys were determined. Optical microscopy (OM), scanning electron microscopy (SEM), immersion corrosion, electrochemical corrosion experiments, and tensile testing were performed. Research has found that combining hot extrusion with subsequent low-temperature annealing significantly improves the strength, plasticity, and corrosion resistance of alloys due to grain refinement and a reduced dislocation density. The alloy was completely recrystallized at an annealing temperature of 240 °C for 4 h after solid solution extrusion, and the grains were fine and uniform, demonstrating the best comprehensive properties. Its corrosion rate, ultimate tensile strength, yield strength, and elongation were 0.454 ± 0.023 mm/y, 346.7 ± 8.9 MPa, 292.4 ± 6.9 MPa, and 19.0 ± 0.4%, respectively. The corrosion mechanism of the specimens under extruded and annealed conditions was analyzed. After annealing at 240 °C for 4 h, the dislocation and bimodal grain structure of the samples were almost eliminated, resulting in uniform and fine grains, which were conducive to the formation of a more uniform and denser oxide film, thus improving the corrosion resistance of the alloy.

Ti/(TiB+TiC) titanium matrix composites with the excellent mechanical properties were prepared by vacuum pressureless sintering and hot extrusion by using low-cost TiH2 powders instead of pure titanium powders and adding B4C to in-situ produce TiB and TiC reinforcements. The effects of preparation technology and reinforcements on the microstructure and properties of the Ti/(TiB+TiC) composites were analyzed. The results show that the TiH2 powders have the good sintering activity, and the relative density of the sample after dehydrogenation and sintering can reach 97.7%, which is further increased to 99.9% after the hot extrusion as closed to full density. The TiB reinforcements are short fibrous, and the TiC reinforcements are granular, which are uniformly distributed in the equiaxed α-Ti matrix, restraining the growth of equiaxed grains and refining the grains. The hot extrusion process can further refine the grains and make the microstructure more uniform and compact, the as-extruded titanium matrix composites show the high hardness and good matching of strength and ductility. The TiH2+4%B4C (volume fraction) extruded composites have the Vickers hardness of Hv0.3 310, yield strength of 683 MPa, tensile strength of 851 MPa, and elongation of 15.1% after fracture.

Alloy composition and heat treatment processes have limited possibility to enhance ultra‐high strength of aluminum alloys, which restricts their widespread application in lightweight equipment. Consequently, high‐density dislocations and grain refinement are suggested to strengthen ultra‐high strength aluminum alloys. Herein, a novel nanostructured Al–Zn–Mg–Cu–Zr–Sc (AZMCZS) alloy with homogeneous microstructure is prepared through the synergistic processing of hot extrusion and high‐pressure torsion. Additionally, the microstructures and strengthening mechanisms of the nanostructured Al alloy are analyzed. It is observed that the ultimate tensile strength of the nanostructured Al alloy reaches nearly 1 GPa, and the elongation of the alloy is 1.9%. The nanostructured Al alloy mainly consists of nanoscale grains (≈117.7 nm), high‐density dislocations (2.4 × 1015 m−2), nano‐sized precipitates (the size of 20–51 nm), and solute atom clusters (≈3 nm). The multiple strengthening mechanisms of the nanostructured Al alloy are revealed in terms of grain refinement, dislocations, precipitates, and solute atom clusters. Grain refinement and dislocation strengthening show superior outcomes and are considered to be the predominant strengthening mechanisms. These findings demonstrate that this nanostructural architecture offers a new way to design super‐strength metals and alloys by effectively controlling the processing regime of severe plastic deformation. [ABSTRACT FROM AUTHOR]

In this investigation, the effects of different annealing temperatures (180, 200, 220, 240, 260, and 280 °C) on the microstructure evolution and properties of an extruded Mg–2.0Zn–1.0Y–0.5Zr (wt%) magnesium alloys were determined. Optical microscopy (OM), scanning electron microscopy (SEM), immersion corrosion, electrochemical corrosion experiments, and tensile testing were performed. Research has found that combining hot extrusion with subsequent low-temperature annealing significantly improves the strength, plasticity, and corrosion resistance of alloys due to grain refinement and a reduced dislocation density. The alloy was completely recrystallized at an annealing temperature of 240 °C for 4 h after solid solution extrusion, and the grains were fine and uniform, demonstrating the best comprehensive properties. Its corrosion rate, ultimate tensile strength, yield strength, and elongation were 0.454 ± 0.023 mm/y, 346.7 ± 8.9 MPa, 292.4 ± 6.9 MPa, and 19.0 ± 0.4%, respectively. The corrosion mechanism of the specimens under extruded and annealed conditions was analyzed. After annealing at 240 °C for 4 h, the dislocation and bimodal grain structure of the samples were almost eliminated, resulting in uniform and fine grains, which were conducive to the formation of a more uniform and denser oxide film, thus improving the corrosion resistance of the alloy. [ABSTRACT FROM AUTHOR]

Bi1−xSbx crystal is one of the best n-type thermoelectric materials below 200 K, but its weak mechanical strength hinders practical applications for deep refrigeration. Herein, we adopted the mechanical enhancement method of hot extrusion to investigate the comprehensive mechanical and thermoelectric properties of Bi0.905Sb0.095. It revealed that reducing the grain size of the matrix and increasing the extrusion ratio can improve the gain size uniformity and mechanical properties. Meanwhile, the thermoelectric performance depends on the texture, grain size, and local composition. The extruded sample prepared by ingot with the high extrusion ratio of 9:1 generated uniform small grains, which resulted in the high bending strength of Bi1−xSbx~130 Mpa and a high power factor of ~68 μW·cm−1·K−2@173 K, as well as the relatively high figure of merit of 0.25@173K. This work highlights the importance of the uniform distribution of the grain size and the compositions for Bi1−xSbx, as well as the required universal key parameter for the hot extrusion method. [ABSTRACT FROM AUTHOR]

Microstructure, mechanical and corrosion properties of hot-extruded Mg-2.0Zn-0.4Mn with varying Al addition were investigated in this study. The results demonstrate that adding Al to Mg-2.0Zn-0.4Mn promotes dynamic recrystallization significantly during hot extrusion and improves the tensile mechanical properties and corrosion resistance of the hot-extruded alloy. The dynamic recrystallized grain sizes decrease while the fraction of dynamic recrystallization area increases with Al addition. This is owing to the promoted recrystallization nucleation rates attributed to the grain refinement or increased amount of grain boundaries in solutionized alloy and particle stimulated nucleation by undissolved second-phase particles. The quantity and size of second phase particles of extruded alloys also increase with Al addition, which, in turn, contributes to the refinement of recrystallized grains by grain boundary pinning effect. As a result, tensile properties of the extruded alloy have improved by alloying with Al, owing to the coupling effects of more solute atoms, reduced recrystallized grain size and presence of fine second-phase particles. The improved corrosion resistance of extruded alloys by Al addition is mainly attributed to Al solute atoms and relatively uniform extruded microstructure that facilitate the formation of a more compact passive film. However, galvanic corrosion induced by second-phase particles and the Mg matrix significantly mitigates this effect. Consequently, optimized Al addition to this extruded Mg-2.0Zn-0.4Mn alloy is determined to be 4 wt.%. [ABSTRACT FROM AUTHOR]

The coefficient of thermal expansion mismatch (CTEM) strengthening is presumed to be among the main strengthening factors in metal matrix composites reinforced with micro- and nano-sized particulates. It is assumed that the CTEM-generated dislocations obstruct the movement of those generated, when the composite is under external load, thus strengthening the composite. An experimental study, which was carried out on as-produced aluminum-based composite, reinforced with 5 and 10 wt.% nano-sized TiCN particulates (volume fraction of TiCN, fv = 0.0306 and 0.0625), failed to detect the predicted by the theory CTEM-generated dislocations. Moreover, it was found that the reinforcement-matrix adhesion forces become weaker with the increase in the reinforcement size. An analysis of the experimental results, intended to investigate the contradiction between the experiment and the postulates of the CTEM strengthening theory, was carried out. The analysis, that implements the dislocation nucleation (Cottrell) and vacancy "drift-diffusion" (Einstein–Smoluchowski) theories, revealed that the classical CTEM strengthening mechanism is active only above a certain, critical size, of the reinforcement. It was found that below that critical size, the composite strength is controlled by the adhesion forces between the reinforcement and the matrix. The theories above predicted that the composite strength (i) would improve as the size of the reinforcement tends to the nano-scale sizes, and (ii) is at its lowest when the size of the reinforcement is commensurate with the aforementioned critical size. [ABSTRACT FROM AUTHOR]

Climate change is a significant global environmental issue that has attracted extensive research and debate. Consequently, the concept of sustainability in the context of aluminium encompasses multiple dimensions. Within the discussions surrounding waste and resource management, there is ongoing deliberation about the actual environmental advantages offered by material recycling. The high demand for raw materials has prompted researchers to explore sustainable recycling processes, with a particular focus on processing technologies. A comprehensive examination of these diverse methods is crucial for understanding three main techniques for aluminium forming: conventional recycling (CR), semi-direct recycling (SDR), and direct recycling (DR). Through a systematic review, it becomes evident that SDR and DR, which incorporate a forming process, present substantial environmental, energy, and cost benefits while promoting sustainability awareness in the manufacturing sectors. This extensive review also encompasses nine life cycle analysis (LCA) studies, comprising sixteen scenarios that have employed various methodologies to assess the environmental impact of managing waste aluminium through different approaches: recycling (melting and solid-state), incineration, or landfill. The outcomes of this comprehensive international review provide a more unbiased evaluation of the environmental effects associated with various wastes management systems. The majority of the studies indicate that recycling offers superior environmental solutions and fewer environmental effects compared to alternative waste green forming management options.

Good strength-ductility balance in graphene nanosheet (GNS)-reinforced aluminum nanocomposites can be achieved through tailorable and facile agglomeration control. Our previous study showed that pre-modulating the Al powder morphology by adding hard silicon carbide nanoparticles (SiCnp) during the two-step ball milling process effectively promotes the uniform dispersion of GNSs. However, excess SiCnp content causes SiCnp aggregate and premature cracking of composites. Here, GNS-reinforced aluminum nanocomposites with different SiCnp content (0.3–1.5 vol%) were prepared, and the optimal SiCnp-to-GNS ratio was determined after optimizing the SiCnp content in a pre-studied composite preparation process. The effect of SiCnp on the microstructure and mechanical properties of the composites was systematically investigated. The cold welding deformation of Al flakes increased with the SiCnp content. Nonetheless, inadequate or excessive SiC content caused insufficient lamination or excessive cold-weld stacking of Al flakes, respectively. Al-0.9vol.%SiCnp powders possessed the highest specific surface area which resulted in high homogeneous dispersion of 3.0 vol% GNS during the second ball-milling stage. Consequently, the resulting hybrid reinforced (GNS + SiCnp)/Al composites showed simultaneous improvement in strength and plasticity, unlike Al-3.0vol.%GNS composites. This showed that introducing hard nanoparticles (i.e., the hybridization strategy) is a promising method to simultaneously enhance strength and plasticity of aluminum nanocomposites.

Abstract In a bid to address the energy-intensive nature of primary aluminum production, this study explores the solid-state recycling of aluminum alloy 6082 chips through direct hot extrusion. Compacted at room temperature, chips were extruded at temperatures (350, 425, and 500 °C) and reduction ratios (6, 8.5, and 11) to optimize mechanical properties. Extensive analyses, including ANOVA and linear regressions, of strength, density, and microstructure revealed significant influences of those extrusion parameters. Optimizing these parameters within the study's aforementioned working ranges can impact the recycled material's strength; with a 36% reduction ratio increase and 20% temperature increase modestly reducing ultimate strength (2%), while a 20% temperature increase alone lowers yield strength more noticeably (9%). These findings highlight the potential for enhanced recycling and sustainable manufacturing.

A novel magnesium-based multi-principal element alloy with the chemical formula Mg54Al22Li11Zn11Ti2 was prepared using the vacuum induction melting method and subsequently extruded at 350 °C. The phase composition of the alloy in its as-cast state and the microstructural changes after extrusion were investigated using various analytical techniques, including SEM, EBSD, EPMA, and TEM. The presented outcomes showed that the as-cast alloy exhibited lattice distortion and fine grain with segregation, while the average grain size decreased significantly and the second phase became more dispersed after extrusion. The mechanical properties of both the as-cast and extruded alloys, including microhardness, tensile strength, compressive strength, and wear characteristics, were evaluated. The extruded alloy demonstrated significant improvements in mechanical properties compared to the as-cast alloy, with a compressive strength of up to 460 MPa, which can be attributed to both fine grain and precipitation strengthening. Both the as-cast and extruded alloys exhibited high hardness due to the accumulation of local dislocations caused by the interlaced precipitation of sub-grains during the super-solid solution state in the as-cast condition. The hardness enhancement in the extruded state resulted from grain refinement induced by DRX. Furthermore, wear tests revealed that the extruded alloy, characterized by smaller second phase sizes, exhibited excellent wear resistance, with wear failure occurring in the form of abrasive and oxidative wear in both the cast and extruded alloys.

The hot deformation behavior of modified N50 austenitic stainless steel in the temperature range 950∼1250 °C and strain rate range of 0.01–50/s was studied by uniaxial compression experiment. The processing map and the constitutive equation for the finite element simulation were established, and the recrystallization mechanism was discussed. The results indicated that the dominant deformation mode DDRX (discontinuous dynamic recrystallization) increased with the rise of deformation temperature while the CDRX (continuous dynamic recrystallization) was on the contrary. There is a decrease in global recrystallization with increasing strain rate, up to a threshold 1/s beyond which the global recrystallization began significantly promotion owing to not only the adiabatic heat and higher stored energy, but also quick Post-DRX mechanism induced by delay quenching. The reasonable hot working interval was determined by a hot working map, then the most suitable hot extrusion parameters (1180°C-100 mm/s) were further obtained with the help of finite element simulation, and ultimately, the industrial hot extrusion trials of N50 pipes with Post-DRX features were further completed. The tensile performance of final jacket pipes was far beyond the current mainstream low-temperature austenitic structural steel and met the requirements of the new generation of superconducting coil jacket materials.

For atmospheric melting cast Cu–15Ni–8Sn alloy, hot extrusion tests were conducted on ingots of Cu–15Ni–8Sn alloy with varying extrusion ratios (5, 12 and 16) following homogenization and annealing. The investigation employed mechanical property tests, scanning electron microscopy and transmission electron microscopy to analyze the mechanical characteristics, dynamic recrystallization and twinning behaviors of the alloys subjected to different extrusion ratios. The findings revealed a reduction in the average grain size of the alloy as the extrusion ratio increased. The alloy undergoes dynamic recrystallization during hot extrusion, and the degree of recrystallization of the alloy escalated with higher extrusion ratios. The alloy underwent completely recrystallized at an extrusion ratio of 16, primarily driven by discontinuous dynamic recrystallization (DDRX). In addition, the alloy generated twins during the DRX process, and the twin boundaries provided favorable sites for the nucleation of DRX grains, which promoted the DRX of the alloy. Notably, at an extrusion ratio of 16, the alloy demonstrated impressive mechanical properties, with an ultimate tensile strength of 836 MPa and an elongation of 13.5 %. These results presented a substantial enhancement, showcasing a 54 % increase in the extruded ultimate tensile strength and a 350 % increase in the elongation compared to that of the alloy in the homogenized annealed state.

The demand for high‐performance materials in thermoelectric (TE) technology has driven continuous efforts to enhance the performance of commercialized Bi2Te3‐based thermoelectric materials. Here, we report success in achieving significant performance improvements in n‐type Bi2Te2.8Se0.2S0.01 through the implementation of a hot extrusion manufacturing process. This tailored manufacturing process has yielded a desired microstructure characterized by grain growth and preferred orientations. The resulting enlarged grain‐based microstructure exhibits reduced dislocations and defects that originated from plastic deformation during extrusion and post annealing. As such, the charge carrier mobility is significantly enhanced, leading to an ultrahigh power factor of approximately 51 μW cm−1 K−2 at ambient temperature. Consequently, a maximum figure of merit (zT) of 1.12 is achieved at 348 K in the combination of extrusion and annealing procedures. Using the synthesized n‐type Bi2Te2.8Se0.2S0.01 material, full‐scale cooling modules have been fabricated. These modules demonstrate record cooling performance, with a maximum temperature difference (ΔT) of 73.9 K at a hot‐side temperature of 300 K and a maximum cooling power density of 2.2 W cm−2. The cooling performance of these TE devices surpasses that of commercially available devices, establishing their potential for next‐generation TE cooling applications. [ABSTRACT FROM AUTHOR]

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3003 aluminum alloy exhibits commendable corrosion resistance, ease of processing, and good formability, rendering it extensively utilized across many industrial sectors. In this study, the corrosion behavior of 3003 aluminum alloy in a homogenized state and after hot extrusion deformation in an acidic salt spray environment for different times was studied. The microstructure of the 3003 aluminum alloy in the homogenized state and after hot extrusion was characterized using scanning electron microscopy (SEM), optical microscope (OM), laser scanning confocal microscope (LSCM) etc., while electrochemical methods were employed to study the difference in corrosion resistance between these two states. The results show that corrosion pits on the surface of the homogenized 3003 aluminum alloy increase with time, and corrosion extends along the second phase arrangement, while the hot extruded 3003 aluminum alloy mainly exhibits corrosion pit extension. The grain size of the homogenized 3003 aluminum alloy is larger than that of the hot extruded state, and the second phase is distributed in a reticular pattern. Hot extrusion deformation ensures not only a uniform distribution of the second phase in the 3003 aluminum alloy but also a reduced grain size, an increased grain boundary density, a heightened electrochemical activity in acidic environments, and an augmented pitting density. Compared with the homogenized 3003 aluminum alloy, the pitting density, maximum pitting depth, and weight loss of the hot extruded state are increased. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Beijing University of Technology is the property of Journal of Beijing University of Technology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper investigates the stress and strain state as well as formation processes of structure and features of aluminum alloys during the hot extrusion. It has been shown that during the hot extrusion the ring layers of an extruded element experience not only longitudinal and transverse deformations, but also a slip. The slip increases from inner layers to the surface layer. The tensile principal stresses and the sum of slip deformations also increase. It has been also demonstrated that at the exit of the pressing part the tensile principal stresses have different directions, forming an angle with extruder axis, which also increases towards the surface. In conclusion, it has been stated that the main radial and circumferential deformations act as restraining deformations. [ABSTRACT FROM AUTHOR]

Al–50Si alloys were prepared by powder extrusion and characterized for electronic packaging. The optimization of powder size, extrusion temperature, and heat treatment parameters was performed to enhance the microstructure and thermo-physical properties. The alloy exhibits a high relative density >99 %, a low coefficient of thermal expansion (CTE)

The microstructure evolution and corrosion mechanism of Mg–9Er–xGd–2Ni alloys, subjected to Gd addition and extrusion, were investigated in this study. Results shows that with the increase in Gd content from 1.0 wt.% to 5.0 wt.%, the second phase change from continuous network LPSO phase with intragranular γʹ phase to a monolithic continuous network LPSO phase, while the corresponding volume fraction of the second phase remains essentially unchanged. Moreover, it is noted that increasing Gd content contributed to a reduction in the corrosion rate of alloy by reducing galvanic corrosion couples and facilitating the formation of double Gd2O3 and Er2O3 corrosion-resistant films. Ultimately, what's most noteworthy is that compared with as-cast alloys, the corrosion rate of as-extruded alloys increased by 49.2%–125.3% with increasing Gd content, which is due to the streamlined LPSO phase distribution weakening the corrosion barrier effect of high-volume fraction network distribution LPSO phase alloy and grain refinement providing more corrosion interfaces that inhibited the formation of corrosion-resistant product films. This study provides new provides new insights for the development of highly degradable Mg–Er–Gd–Ni alloys that have high strength potential for applications in unconventional oil and gas extraction.

This paper investigates the microstructure, texture, and mechanical properties of the Mg-4Zn-1Mn-0.5Ca alloy subjected to hot extrusion under varying conditions of temperature (260 °C, 300 °C, 340 °C) and extrusion speed (0.01 mm/s, 0.1 mm/s, 1 mm/s). The primary objective is to determine the optimal extrusion parameters within the selected experimental range for achieving superior mechanical properties. The results indicate that, when extruded at a constant speed of 0.1 mm/s, the alloy exhibits optimal performance at 340 °C, with a yield strength of 202 MPa, ultimate tensile strength (UTS) of 306 MPa, and elongation at fracture of 18.9%. A decrease in extrusion temperature leads to an increase in yield strength but a reduction in ductility. Specifically, the UTS reaches its peak at 342 MPa at 300 °C, while it drops slightly to 329 MPa at 260 °C. The final results show that the comprehensive mechanical properties of the Mg-4Zn-1Mn-0.5Ca alloy obtained by hot extrusion treatment with an extrusion temperature of 300 °C and extrusion speed of 0.1 mm/s are the best and can effectively improve the mechanical properties of the alloy and provide a good choice for the preparation of other biodegradable magnesium alloy products.

Artificial intelligence methods, especially artificial neural networks (ANNs), have increasingly been utilized for the mathematical description of physical phenomena in (metallic) material processing. Traditional methods often fall short in explaining the complex, real-world data observed in production. While ANN models, typically functioning as “black boxes”, improve production efficiency, a deeper understanding of the phenomena, akin to that provided by explicit mathematical formulas, could enhance this efficiency further. This article proposes a general framework that leverages ANNs (i.e., Conditional Average Estimator—CAE) to explain predicted results alongside their graphical presentation, marking a significant improvement over previous approaches and those relying on expert assessments. Unlike existing Explainable AI (XAI) methods, the proposed framework mimics the standard scientific methodology, utilizing minimal parameters for the mathematical representation of physical phenomena and their derivatives. Additionally, it analyzes the reliability and accuracy of the predictions using well-known statistical metrics, transitioning from deterministic to probabilistic descriptions for better handling of real-world phenomena. The proposed approach addresses both aleatory and epistemic uncertainties inherent in the data. The concept is demonstrated through the hot extrusion of aluminum alloy 6082, where CAE ANN models and predicts key parameters, and ChatGPT explains the results, enabling researchers and/or engineers to better understand the phenomena and outcomes obtained by ANNs.

In this paper, the effect of extrusion temperatures (250 °C, 300 °C and 350 °C) on the microstructure, second phases particle, texture, and mechanical properties of the Mg–5Sn–1Si–0.6Ca alloy were discussed. The results show that after extrusion the second phases in the alloy were broken and distributed along the grain boundary. Decreasing the extrusion temperature is beneficial to dynamic precipitation and grain refinement. During the extrusion process, a large number of Mg2Sn nanoprecipitates are dynamically precipitated from the Mg matrix and their number increased and their size decreased with the decrease of extrusion temperature. The grain size was refined from 5.8 μm to 3.328 μm with the extrusion temperature decreasing from 350 °C to 250 °C. Besides, the texture intensity was also reduced with the decrease in extrusion temperature. The strength and plasticity of the Mg–Sn–Si–Ca alloys are simultaneously improved by the method of “solid solution + low-temperature extrusion”. When the extrusion temperature is 250 °C, the alloy obtains superior engineering mechanical properties with the yield strength of 287 MPa, ultimate tensile strength of 343 MPa and elongation to failure of 23.3%. The high strength is mainly attributed to the combined effect of grain size, weak texture, and high density of precipitation. The good ductility is mainly attributed to the grain refinement and high Schmid factors of basal slip.

Hot extrusion process can improve the mechanical properties of materials. However, due to the presence of SiC particles, SiCp/Al composites are prone to fracture damage in the extrusion process. To determine the optimal processing parameters, the processing maps of 17 vol.% SiCp/2009Al composite were established using power dissipation rate and Murty instability criterion. Furthermore, taking aluminum canning into consideration, a three-dimensional macroscopic hot extrusion finite element model of SiCp/Al composite was constructed. The influences of initial temperature, canning morphology and canning thickness on extrusion properties were predicted, and verified by comparison of processing maps and experiments. The optimal extrusion parameters for SiCp/2009Al composite are located within the window of temperature, 450–475 °C and strain rate, 0.001–0.004 s−1 or 0.6–1 s−1. Additionally, the properties of the SiCp/Al composite can be greatly improved by hot extrusion with a suitable canning. Of these, the half canning finish the extrusion task faster, but the extrusion properties under the bottom canning are the best. When the ratio of the canning thickness to the diameter of the workpiece is about 0.17, the effective stress, strain and damage are minimum. The work performed in this research, for the first time, provides quantitative evaluations of process parameters on the hot deformation of SiCp/Al composite, which enables to provide useful guides for hot extrusion parameters selection of SiCp/Al composite.

Aluminum alloy has the characteristics of light weight, high strength, corrosion resistance, easy forming, etc., and is widely used in manufacturing industry. The extrusion speed of aluminum alloy rim is not uniform, which affects the mechanical properties of the product. In order to solve these 1problems, the finite element analysis model of hot extrusion of aluminum alloy profiles was established in HyperXtrude software. The influences of different bar diameters, hot extrusion velocity, bar preheating temperature, die temperature and extrusion cylinder temperature on velocity difference and maximum extrusion pressure at the exit were analyzed. The results show that the designed hot extrusion rim die meets the requirements of strength and deformation, and the best extrusion process parameters of 7075 aluminum alloy rim profiles in improving profile quality and reducing energy consumption are obtained by Taguchi test gray correlation method.

This paper investigates the stress and strain state as well as formation processes of structure and features of aluminum alloys during the hot extrusion. It has been shown that during the hot extrusion the ring layers of an extruded element experience not only longitudinal and transverse deformations, but also a slip. The slip increases from inner layers to the surface layer. The tensile principal stresses and the sum of slip deformations also increase. It has been also demonstrated that at the exit of the pressing part the tensile principal stresses have different directions, forming an angle with extruder axis, which also increases towards the surface. In conclusion, it has been stated that the main radial and circumferential deformations act as restraining deformations.

The demand for high‐performance materials in thermoelectric (TE) technology has driven continuous efforts to enhance the performance of commercialized Bi2Te3‐based thermoelectric materials. Here, we report success in achieving significant performance improvements in n‐type Bi2Te2.8Se0.2S0.01 through the implementation of a hot extrusion manufacturing process. This tailored manufacturing process has yielded a desired microstructure characterized by grain growth and preferred orientations. The resulting enlarged grain‐based microstructure exhibits reduced dislocations and defects that originated from plastic deformation during extrusion and post annealing. As such, the charge carrier mobility is significantly enhanced, leading to an ultrahigh power factor of approximately 51 μW cm−1 K−2 at ambient temperature. Consequently, a maximum figure of merit (zT) of 1.12 is achieved at 348 K in the combination of extrusion and annealing procedures. Using the synthesized n‐type Bi2Te2.8Se0.2S0.01 material, full‐scale cooling modules have been fabricated. These modules demonstrate record cooling performance, with a maximum temperature difference (ΔT) of 73.9 K at a hot‐side temperature of 300 K and a maximum cooling power density of 2.2 W cm−2. The cooling performance of these TE devices surpasses that of commercially available devices, establishing their potential for next‐generation TE cooling applications.

This work proposes a new neutron absorber, Cu–B composites, with excellent thermal conductivity and good neutron absorbing capability. Mixtures of elemental Cu and B powders with the B contents varying between 10 and 40 at.-% were consolidated into round bars by hot extrusion. The addition of B significantly refined the grain structure, which is related to the suppression of dynamic recrystallisation during hot extrusion and extended recovery during subsequent annealing. Such fine-grained structure in Cu–B composites together with dispersion hardening by B particles contributed to the higher hardness of Cu–B composites. The thermal conductivity of Cu–B composites, being roughly two times higher than that of Al–B4C MMC, decreases with increasing the B contents, which is mainly due to higher volume fraction B particles with lower thermal conductivity, and partly to texture randomisation and refined grain structure in the Cu–B composites. [ABSTRACT FROM AUTHOR]

The article provides systematization and comparative analysis of data for structural and phase states and set of physical and mechanical properties formed in deformable tube semi-finished products. Analysis includes various stages of obtaining hot-extruded tubes of titanium alloys PT-1M, PT-7M, Ti–3Al–2.5V. The relationship between characteristics of macro-, microstructure, parameters of the phases formed with spread of hardness values in the original hot-forged tube billets is established. Physical simulation of hot deformation processes of alloys with varying temperature and upsetting deformation rate is conducted. Recommendations for extrusion temperature ranges for each alloy are proposed. These recommendations are based on energy-power parameters of industrial equipment used and restrictions imposed by the structure. Evolution of the structure and change in hardness during expansion of a tube billet made from the alloys investigated are considered. Results of computer simulations of energy-power parameters of tube extrusion and their comparison with industrial experiment data are presented. Features of the structure, texture and their relationship with tube mechanical properties are established. [ABSTRACT FROM AUTHOR]

The high temperature compression test of Be/2024Al composites with 62wt% Be was conducted at 500–575°C and strain rate of 0.003–0.1 s−1. The strain-compensated Arrhenius model and modified Johnson–Cook model were introduced to predict the hot deformation behavior of Be/2024Al composites. The result shows that the activation energy of Be/2024Al composites was 363.364 kJ·mol−1. Compared with composites reinforced with traditional ceramics, Be/2024Al composites can be deformed with ultra-high content of reinforcement, attributing to the deformable property of Be particles. The average relative error of the two models shows that modified Johnson–Cook model was more suitable for low temperature condition while strain-compensated Arrhenius model was more suitable for high temperature condition. The processing map was generated and a hot extrusion experiment was conducted according to the map. A comparation of the microstructure of Be/2024Al composites before and after extrusion shows that the Be particle deformed coordinately with the matrix and elongated at the extrusion direction. [ABSTRACT FROM AUTHOR]

In this study, hot extrusions at 460, 470, 480, 490, and 500 °C were carried out on 0.5 wt.% graphene nanoplatelet-reinforced aluminum (0.5 wt.% GNPs /Al) composite prepared by powder metallurgy and hot pressing. The microstructure and mechanical properties of hot extruded composite were investigated. The reinforcement effect of hot extrusion on GNPs/Al composite is the synthetic actions of work hardening, dynamic recovery and dynamic recrystallization of matrix grains, and the dispersion, delamination and structure of the GNPs in the composite due to the different fluidity of the matrix at different temperatures. As a result, the comprehensive mechanical properties of the composite extruded at 490 °C are the best. The TEM image exhibits that, at the optimal extrusion temperature of 490 °C, GNPs are uniformly distributed in the aluminum matrix, mainly dispersed at the grain boundaries, where some Al4C3 and Al2O3 exhibit pinning effects to form fine interface between the GNPs and the matrix. [ABSTRACT FROM AUTHOR]