Extrusion Ratio Research Articles

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.

Investigation of Microstructure and Mechanical Properties of Extruded Mg-6Bi and Mg-6Bi-1Ag Alloys.

The extruded Mg-6Bi alloy and Mg-6Bi-1Ag alloy subjected to extrusion at 300 °C with the extrusion ratio of 25:1 and die-exit speed of 2 m/min were used to investigate microstructure characteristics and mechanical behavior. The experimental results demonstrate that the bimodal microstructure, composed of coarse dynamic unrecrystallized (unDRXed) grains and fine dynamic recrystallized (DRXed) grains, was obtained after extrusion. The Ag addition can obviously promote dynamic recrystallization and average grain size. It also indicates that the dynamic precipitation is significantly promoted by Ag addition during extrusion, obtaining more fraction of the Mg3Bi2 precipitates. Moreover, the extruded Mg-6Bi-1Ag alloy has a high tensile yield strength of 304 ± 2.0 MPa, which is increased by 19% compared to the extruded Mg-6Bi alloy, and elongation of 11.0 ± 1.7%, almost the same as 11.9 ± 0.9% of the extruded Mg-6Bi alloy. This result also shows that the extruded Mg-6Bi-1Ag alloy exhibits better strain hardening capacity. Therefore, Ag exhibits an effective role in promoting dynamic recrystallization and dynamic precipitation, resulting in the enhancement of strength and strain hardening capacity of the extruded Mg-6Bi-1Ag alloy, as well as keeping high ductility.

Microstructure and Mechanical Property of the Large Cross-Sectioned Mg–Gd–Y–Zn–Zr Alloy Produced by Small Extrusion Ratio

Microstructure and Mechanical Property of the Large Cross-Sectioned Mg–Gd–Y–Zn–Zr Alloy Produced by Small Extrusion Ratio

Effects of hot extrusion on compressive strength and densification of aluminium-based metal matrix composites

ABSTRACT Metal matrix composites (MMC) made from powder metallurgy (PM) require post-processing to improve the mechanical properties or achieve the final shape. In this experimental study, Aluminium metal matrix composite (Al-MMC) was first fabricated through PM, followed by a hot extrusion process to study the effects of extrusion on compressive strength and density. Hot extrusion of Al-MMC results in microstructure refinement, enhanced dispersion of reinforcement particles and improved mechanical properties. The experimental findings revealed that hot extrusion of Al-MMC resulted in densification, reflected as an average improvement of 5% in the density. An average improvement of up to 22% was observed in the compressive strength of the Al-MMC. Therefore, hot extrusion can be considered an effective post-processing method for enhancing the Al-MMC fabricated through PM. It was also found experimentally that the extrusion ratio also affects the mechanical properties and performance of Al-MMC. It was revealed that the compressive strength is enhanced with an increase in extrusion ratio. It is also important to note that the PM process is one of the processes which offers reasonable control over the utilisation of starting material. Hence, reinforcement retention is higher than other methods like stir casting.

The extrusion ratios modification of Mg-2Gd-xMn alloys to exploration of the strengthening mechanisms

Enhancing the strength of magnesium alloys, a lightweight material, is crucial in promoting its widespread adoption and utilization. In this comprehensive study, the effects of various extrusion ratios and manganese contents on the properties of Mg-2Gd-xMn alloys have been rigorously examined using state-of-the-art techniques such as Electron Backscatter Diffraction (EBSD) and Transmission Electron Microscopy (TEM). Observations reveal that the microstructure of as-extruded Mg-2Gd-xMn alloys typically exhibit a bimodal structure, characterized by a mix of equiaxed recrystallized grains and elongated unrecrystallized grains. The reduction of the extrusion ratio reduces the deformation energy that promotes the nucleation and growth of recrystallization, which effectively reduces the alloy recrystallization grain size and increases the volume fraction of the unrecrystallized microstructure. The uncrystallized microstructure have a significant fiber texture that poses challenges in activating basal slip and is accompanied by a more pronounced work-hardening trend. Additionally, the investigation reveals the vital role of α-Mn particles in obstructing dislocation movement and refining the grains, thereby contributing to enhanced alloys strengthening. Therefore, by harnessing the synergistic strengthening effects of the aforementioned mechanisms, the Mg-2Gd-2Mn alloy demonstrates significantly improved yield strength and tensile strength, reaching an impressive 240 MPa and 281 MPa, respectively.

Effect of extrusion ratio on microstructures, mechanical properties, and high cycle fatigue behavior of Mg–5Zn–1Mn alloy

The effects of extrusion ratio (ER) on the microstructures, static mechanical properties, and tension-compression high cycle fatigue (HCF) behavior of the as-extruded Mg–5Zn–1Mn (ZM51) alloy was investigated systematically, and the HCF mechanism was discussed. The results show that texture weakening and grain refinement caused by increasing the ER can effectively enhance the static mechanical properties and alleviate the tensile-compressive asymmetry of the alloy. The fatigue strength at 107 cycles is 124 ± 5, 138 ± 4, and 142 ± 5 MPa for ER8, ER11.5, and ER23, respectively, and the corresponding fatigue ratio is approximately 0.45, 0.49, and 0.50, which means that the as-extruded ZM51 alloy possesses outstanding fatigue resistance. The failure analysis and microstructure evolution of post-fatigued samples demonstrated that the stress amplitudes and microstructure characteristics strongly influence the HCF mechanism of the alloy. At high-stress load, close to the tensile yield strength 160–180 MPa, abundant {101‾2} residual twin bands were observed near the fracture surface. Twinning/detwinning deformation is the dominant fatigue mechanism due to the plastic deformation incompatibility between the matrix and the residual twins. At low-stress load, close to the fatigue strength 125–145 MPa, the fatigue crack initiation mechanism transits from twinning/detwinning to dislocation slip. Grain refinement and texture weakening inhibit the activation of {101‾2} twins, alleviate the twin-dislocation interaction, and promote dislocation slip to dominate the fatigue deformation, thereby enhancing the fatigue life of the alloy. This work provides new insight into the design and development for enhancing the fatigue resistance of wrought Mg alloy to ensure the long-term service safety of structural materials.

Effects of extrusion temperature and extrusion ratio on the microstructure and properties of Mg–5Sn–1Ca alloy prepared by continuous squeeze casting-extrusion process

In this study, a high-strength and high-toughness Mg–5Sn–1Ca (i.e., TX51) alloy was produced through a continuous squeeze casting-extrusion (CSCE) process without billet homogenization or secondary preheating for the first time. Effects of extrusion temperature and extrusion ratio on the microstructure and mechanical properties of extruded TX51 alloy were investigated. The results show that the CaMgSn eutectic in the as-cast billet was crushed during the CSCE process and exerted the particle stimulated nucleation (PSN) effect, which stimulated dynamic recrystallization of α-Mg. Improper extrusion temperature and extrusion ratio will lead to incomplete recrystallization or grain growth in the extruded alloy, whereas the average grain size of CSCE TX51 alloys can be as small as 2 μm under appropriate process parameters. Interestingly, the TX51 alloy prepared by the CSCE process achieved an excellent strength-toughness match, with optimal ultimate tensile strength, yield strength and elongation of 277.1 MPa, 233.2 MPa and 23.27%, at an extrusion ratio of 16:1 and an intermittent time of 60s (i.e., extrusion temperature is 246 °C). Based on quantitative calculations, the high strength and plasticity are attributed to four strengthening mechanisms, among which grain boundary strengthening and geometric strengthening are the most important contributors.

Effect of extrusion ratio on microstructure, texture, and mechanical properties of dual-phase Mg−8Li−6Zn−2Gd alloy

The microstructure observation, macrotexture analysis, and tensile test were conducted to investigate the effect of extrusion ratio on the microstructure, texture, and mechanical properties of Mg−8Li−6Zn−2Gd alloy. The results show that the as-homogenized Mg−8Li−6Zn−2Gd alloy consists of α-Mg, β-Li, MgLiZn, I-phase, and W-phase. After hot extrusion, eutectic I-phase is broken into fine particles, while W-phase maintains massive shape. Both α-Mg and β-Li matrices undergo dynamic recrystallization (DRX), and their grains gradually refine with increasing extrusion ratio. For α-Mg matrix, the weakening of basal texture and the strengthening of prismatic texture after hot extrusion are due to the activation of non-basal slip. For β-Li matrix, the appearance of obvious α and γ fiber textures after hot extrusion is associated with the dynamic recovery (DRV) and DRX. The tensile strength and elongation of the alloy are simultaneously improved by hot extrusion, and the best comprehensive mechanical properties are achieved when extrusion ratio is 16:1.

Improvement of strength and ductility of TC4p/AZ91D magnesium matrix composites by modifying the extrusion ratio

In this study, AZ91D (Mg-9Al-Zn) alloys reinforced with 2 vol% TC4 (Ti–6Al–4 V) particles fabricated by semi-solid stir casting were extruded at different ratios, resulting in observed grain refinement effects. The research findings demonstrate that both TC4 and β-Mg17Al12 phases contribute to promoting dynamic recrystallization (DRX) nucleation. With increasing extrusion ratio, the β-phase (Mg17Al12) gradually fractures into smaller particles, leading to progressive grain refinement. Furthermore, the transition from 〈01–10〉 fiber texture to non-basal texture in the α-Mg matrix after hot extrusion is attributed to improved DRX behavior and activation of non-basal slip. As the extrusion ratio increases, the tensile strength and elongation (EL) of TC4p/AZ91D composite improve significantly, reaching optimum comprehensive mechanical properties at an extrusion of 40:1 with a yield strength (YS) of 257 MPa, an ultimate tensile strength (UTS) of 357 MPa, and an EL of 9.7%. This remarkable strengthening effect is primarily attributed to β-phase reinforcement, grain refinement strengthening, and strain hardening.

Study on the microstructure and mechanical properties of VW73B alloy at high extrusion ratio

The microstructure and mechanical characteristics of VW73B prepared by a high extrusion ratio (70:1) were studied. High-strength plastic VW73B alloy containing long-period structural phase (LPSO) was obtained by extrusion process. OM, SEM, TEM, and EBSD were used to investigate the relationship between microstructure and mechanical characteristics of VW73B. The findings indicate that VW73B presents complete dynamic recrystallization after deformation, and there are 14H-LPSO phases, SFs, and a large amount of β´ phase, which are precipitated after aging treatment. The UTS, YS, and EL of VW73B in peak aging state are 406 MPa, 339 MPa, and 9%, respectively. The β´ phase, LPSO phase, poor texture, and fine grain strengthening of VW73B contribute to its exceptional characteristics.

Analysis of the influence of dies geometry on the process extrusion force and properties of the extrudate obtained in the process of cold extrusion of 7075 aluminum alloy by the KOBO method

Abstract The KOBO extrusion process is an unconventional method of extrusion based on the phenomenon of superplasticity as an effect of a special state caused by the oscillatory motion of the die at a certain angle a certain frequency. It significantly lowers the extrusion force and makes it possible to extrude lightweight metals and alloys (e.g. aluminum and magnesium alloys) in cold extrusion with high extrusion ratios compared to conventional hot extrusion. This work studies the influence of the tool (die) geometry on process realization parameters and the properties of the extrudate. Experimental studies of cold KOBO extrusion were performed using dies with different face portion geometry. The obtained extrudate obtained from EN-AW 7075 aluminum billets was examined for mechanical properties and macro/microstructure, showing that, with adequate modifications to the tool face part geometry, it is possible to lower the extrusion force and obtain extrudate with desired properties.

Preparation and efficacy verification of three-dimensional printed partitioned multi-effect precision-care gel facial mask.

A partition multi-effect precision-care gel facial mask conforming to facial skin characteristics was prepared using three-dimensional (3D) printing technology. First, the hydrogel matrix and humectant of a 3D-printed gel for facial masks were screened, and three 3D-printed gels of arbutin, hexapeptide, and salicylic acid were prepared with whitening, wrinkle removal, and oil control functions, respectively. Skin irritation tests were performed on the gels. Physicochemical properties such as pH, heat and cold tolerance were evaluated. The efficacy of three 3D-printed gels was assessed by measuring melanin value, wrinkle depression score, and oil secretion. Finally, the facial mask model design and printing parameters were studied, and a partition multi-effect precision-care gel facial mask was printed in line with facial skin characteristics. For the 3D-printed facial mask, the gel prescription with 2% hydroxyethyl cellulose gel as matrix and 7% glycerol as humectant was the best. The prepared 3D-printed gel did not irritate the human skin, and its physicochemical properties met the Chinese facial mask industry standard (QB/T2872-2017). We showed that three types of 3D-printed gels containing arbutin, hexapeptide, and salicylic acid could be applied to the corresponding parts of the face to solve different problems, such as facial skin dullness, wrinkles, and oil secretion. Therefore, according to facial physiological characteristics, the facial mask model was designed for the forehead and nasolabial fold, which needs to be anti-wrinkled; the cheek, which needs to be whitened; and the nose and chin, which need oil control. The optimal printing parameters were 0.26 mm nozzle diameter, 90 mm/s printing speed, 30% filling density, 140% wire extrusion ratio, and 0.25 mm layer height. Different skin care effects can be achieved using a three-nozzle printer to print arbutin, hexapeptide, or salicylic acid gel on the mask's forehead and nasolabial fold, cheek, and nose and chin, respectively. The 3D-printed partition multi-effect care gel facial mask prepared according to the skin features of different parts of the face can overcome the problem of the single skincare effect of the mass-produced facial masks.

Effects of the Extrusion Ratio on the Microstructure and Mechanical Properties of Columnar Network Structured TiBw/TA15 Composites

Effects of the Extrusion Ratio on the Microstructure and Mechanical Properties of Columnar Network Structured TiBw/TA15 Composites

Influence of Extrusion Ratio on Microstructure and Tensile Properties of Mg–Gd–Y–Zn–Zr Alloy

Influence of Extrusion Ratio on Microstructure and Tensile Properties of Mg–Gd–Y–Zn–Zr Alloy

Numerical and experimental investigations on AA6063 extrudates: effect of number of portholes on extrusion load and weld strength

In aluminium extrusion process, metal flow is greatly controlled by the die geometry and a variety of intricate profiles can be achieved by designing dies of different configurations. In porthole die extrusion, number of portholes used for a profile is often determined by the subjective knowledge of designers. Nevertheless, extrusion load and weld strength of profile produced are not only dependent on extrusion ratio, temperature of deformation but also on the number of portholes along with other die geometry variables. In the present investigation, systematic studies were carried out on three different dies with four ports, three and two ports around die center to extrude profiles of outer diameter 29.4 mm and thickness 2 mm. Numerical simulations were carried out for estimation of pressure, temperature, strain, and strain rate parameters in the weld chamber for all the dies, followed by press trials and profiles produced were subjected to wedge expansion test. The results from numerical simulations indicated that pressure generated inside weld chamber increases with number of portholes. The surface plots indicated highest pressure of about 280 MPa for four port hole and about 276 MPa for three ports die and pressure of about 160 MPa was estimated for two port hole die at the entry of weld chamber , which is 65 mm from profile end. Similarly, temperature at profile exit was 551 °C for four portholes die and 546 °C for three portholes die and 537 °C for two portholes die. Furthermore, press trials indicated peak extrusion loads of 5241 kN, 4406 kN and 3961 kN respectively for four, three and two portholes die. Thus, the peak extrusion load decreased by about 16% for three port and about 25% for two ports die in comparison with four port die. Also, the extruded profiles in wedge expansion test indicated mean compression load of 22.70 ± 0.14 kN in four porthole die, mean compression load 22.29 ± 0.26 kN for three port die and mean compression load of 17.841 ± 0.27 kN.

Tailoring the electrochemical behavior and discharge performance of Mg–Al–Ca–Mn anodes for Mg-air batteries by different extrusion ratios

This work investigates the electrochemical behavior and discharge performance of Mg–3Al-0.4Ca-0.7Mn alloys with three extrusion ratios (ER) of 10, 16 and 25 as anodes for Mg-air batteries. The results show that the ER16 sample has the lowest corrosion current density and the highest corrosion resistance. The corrosion performance of the ER25 sample is slightly reduced due to the excessive discontinuous second phase leading to elevated self-corrosion rate. The alloy exhibits higher discharge voltage and stable discharge process with increasing extrusion ratio. Increasing the extrusion ratio has a homogeneous microstructure, the increase in the area fraction of non-basal oriented grains is conducive to the homogeneous dissolution of the anode and the inhibition of the “chunk effect”. The ER25 sample showed the highest anode efficiency, specific capacity and energy density of 55.73 %, 1306.67 mA h g-1 and 1635.947 mW h g−1 at 20 mA cm−2, respectively.

Exploring the effect of bimodal microstructure on the mechanical properties of Mg–15Er binary alloy by regulating the extrusion ratio

Bimodal-grained Mg–Gd alloys exhibits excellent mechanical strength due to the high solid solubility of Gd element, which facilitates the strong precipitation strengthening. Er element has a higher solid-solubility than Gd in Mg, which may have a great potential in achieving high strength for Mg alloy. In the study, the Mg–15Er alloy with bimodal microstructure of different proportion of two components is fabricated by adjusting the extrusion ratio and microstructures and mechanical properties for the bimodal-structured Mg–15Er alloy are systematically investigated. The results suggest that the ErH2 phase in the Mg–15Er alloys is stable, regardless of the casting state, solid solution state, or extrusion state. Only a small number of dynamic precipitates is formed during extrusion due to the high solid solubility of Er in Mg. Moreover, the formation of dynamic precipitated MgEr3 phase, where the number of Er atoms is greater than that of Mg atoms, also leads to the inability to form high-density precipitates. The larger extrusion ratio results in higher volume fraction of dynamic recrystallization (from 24 % to 89 %), and larger grain size (from 4.1 μm to 7.9 μm). The results show that the ultimate tensile strength decreases from 301 MPa to 235 MPa, and the elongation increases from 12.5 % to 23.5 % with the increase of the extrusion ratio, which are primarily related to the components of unrecrystallized grains and recrystallized grains rather than dynamic precipitates.

Evolution of grain characteristics and dynamic recrystallization behavior of Cu–15Ni–8Sn alloy under different extrusion ratios

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.

Microstructural, corrosion and mechanical properties of a WE43 alloy: conventional extrusion versus SPD

A hexagonal close-packed-structure WE43 alloy was extruded without any preheating of the initial billet using extrusion with an oscillating die to improve the corrosion and mechanical properties. The WE43 alloy was extruded at high ratios of R1 5:1, R2 7:1 and R3 10:1. Electron back-scatter diffraction and transmission electron microscopy were used to determine the microstructural properties of the alloys. The influence of the extrusion method and the extrusion ratios on the corrosion and mechanical properties were investigated. Electrochemical tests were performed, and the corrosion damage was inspected. Tensile tests were made using micro specimens. When compared to conventional extrusion, the microstructural changes obtained with the KoBo method at R1 5:1 increased the corrosion resistance, which was not only due to the grain refinement, but also due to the intensity of the texture. A decline in the corrosion resistance of the alloys deformed at higher extrusion ratios was observed. This was a result of the massive plastic strain imposed by the KoBo die. The room-temperature mechanical properties of the KoBo-extruded alloys were improved. However, at higher temperatures the mechanical properties decreased due to the solutioning of tiny triple precipitates.

Study on the Microstructure and Properties of Mg-Gd-Ni-Y Alloy Containing LPSO Phase

The long-period stacking ordered (LPSO) structure, functioning as a strengthening phase in magnesium alloys, plays a pivotal role in compensating for inherent performance limitations. In this study, an as-cast Mg-Gd-Ni-Y alloy, including the LPSO phase, was initially obtained through an ingot metallurgy process. Subsequently, the alloy underwent distinct thermal treatments: annealing at 500 °C for 10 h, and extrusion using an extrusion ratio of 10 at a speed of 5 mm/s. Comparative analysis of the microstructure and corrosion characteristics was performed across these three alloy states. Comprising primarily of α-Mg, LPSO phase, and eutectic structures (ES), the alloy exhibited distinctive microstructural features. Immersion experiments conducted in a 3.5% NaCl solution revealed that the as-cast alloy displayed the highest dissolution rate at various temperatures, from room temperature, to 50 °C, and 70 °C. Following annealing, a reduction in the second phase content within the alloy significantly contributed to the observed decrease in its dissolution rate. Extrusion processes resulted in a denser network structure within the microarchitecture, to some extent impeding the spread of corrosion to some extent. By emloying scanning Kelvin probe force microscopy (SKPFM) and micro-electrochemical testing, it was discerned that predominantly the electrochemical system involving α-Mg and the second phases predominantly dictated the heightened dissolution rate of the alloy. This study presents valuable insights into understanding the dissolution mechanisms and potential strategies for controlling the dissolution performance of magnesium alloys containing the LPSO phase.