Extrusion Of Alloy Research Articles

High-strength and high-plasticity ZK60 magnesium alloy prepared by rapid solidification and high-speed extrusion

The extrusion speed of ZK60 magnesium alloy is usually lower than 5 m/min. The rapidly solidified (RS) ZK60 magnesium alloy extruded at 350 ℃ with die-exit speeds of 10 m/min, 20 m/min and 30 m/min was investigated. The results reveal that after the RS ZK60 alloy was extruded at different die-exit speeds, the average size of dynamically recrystallized grains is 1.19–1.40 μm, the percent of high-angle grain boundaries (HAGBs) become larger with the average orientation degree of 57.83 ° to 54.81 °, the intensity of texture at (0001)<1̅100> is below 3.4, and the Schmid factors of the prismatic and pyramidal planes reach the high value of no lower than 0.42 overall, while no coarse MgZn phase was observed. The yield tensile strength, ultimate tensile strength and elongation of the RS as-extruded ZK60 magnesium alloy change slowly from 321 to 299 MPa, -355–348 MPa, and -23–27 % when the die-exit speed increase from 10 to 30 m/min, respectively. The ultra-fine grains and disappearance of the coarse low melting-point MgZn phase are the main reasons for the high-speed extrusion, high strength, high plasticity and low texture of the RS as-extruded ZK60 magnesium alloy.

Fatigue strength of welded joints of marine aluminum alloy extrusion stiffened plate considering welding effects

Due to the low stiffness of thin-plate welded structure, the influence of welding effect on fatigue evaluation of thin-plate welded structure cannot be ignored. Extruded stiffened plates are tried to be used in hull structures because of their excellent forming technology, which can greatly reduce welding deformation and defects. By carrying out fatigue tests of extruded reinforced welded joints and traditional T-shaped welded joints, the S-N curves of typical T-welded joints are obtained and compared. Furthermore, the residual stress and welding deformation of stiffened model and traditional T-model are predicted by numerical simulation. The welding effects are introduced into the calculation of hot spot stress as the initial value, and the hot spot stress class curves of extruded reinforced welded joints and traditional T-welded joints are renewed. Compared with traditional welded joints, extruded welded joints are less affected by residual stress and welding deformation. The study revealed that residual stress and welding deformation exhibited a higher sensitivity to the fatigue strength of traditional thin-plate welded structures.

Achieving High Strength-Ductility Synergy in Low-Alloyed Mg-Li-Er Extrusion Alloys via Tailoring Bimodal-Grained Structure.

Low-alloyed Mg-Li-Er alloys were developed in this study and a bimodal-grained structure was obtained by varying the trace Er content and extrusion temperature. The alloys displayed a good strength-ductility synergy, i.e., a tensile yield strength (TYS) of 270 MPa and an elongation (EL) of 19.1%. Microstructural characterization revealed that the formation of numerous submicron Mg24Er5 particles favored a high density of low-angle grain boundaries (LAGBs) inside the deformed grains and inhibited dynamic recrystallization (DRX). The resultant coarse unDRXed grains with a strong basal texture and considerable LAGBs, together with the fine DRXed grains, contributed to the high strength-ductility synergy.

Effect of extrusion and introduction of Cu wire on the microstructure and mechanical properties of the Mg matrix

Composite extrusion of AZ31 Mg alloy and T2 Cu wire was carried out. The interface characteristics, microstructure evolution and mechanical behavior of as-homogenized, single Mg and Mg/Cu composites were analyzed in detail by various analytical methods. The experimental results show that the interface between Cu wire and Mg alloy matrix is better. With the introduction of extrusion and Cu wire, the grains of Mg matrix are continuously refined, the proportion of LAGBs is gradually reduced, and the texture strength is obviously weakened. The Mg matrix in Mg/Cu composites is more conducive to activating various non-basal slip systems than single Mg. Compared with the as-homogenized Mg alloy sample, the elongation (EL), tensile strength (TS) and yield strength (YS) were improved by extrusion and introduction of Cu wire.

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.

Influence of a Preageing Treatment on the Cluster Formation and the Further Ageing Route in Al–Mg–Si Extrusion Alloys

Herein, the influence of one‐ and two‐step preageing treatments prior to the artificial ageing step to peak age condition for three different 6xxx alloys, from low to high alloy content, is investigated. Analysis of the preaged conditions using atom probe tomography (APT) reveals a broad distribution of Mg and Si clusters, with some instances of Guinier‐Preston I zones present. Additionally, the high alloyed system exhibits a growth of precipitates toward a needle‐like shaped. These clusters formed during the preageing treatment serve as nucleation sites in the subsequent artificial ageing treatment, leading to an increase in hardness. Microstructural analysis conducted using transmission electron microscopy and APT demonstrates a reduction in the average precipitate length and a more narrow size distribution for T6 condition. This indicates that the preageing treatment results in a decreased portion of already overaged precipitates compared to the direct aged condition. Consequently, the more narrow size distribution of the precipitates leads to more effective hardening of the material, as a higher portion of precipitates is at or close to their optimum size. The investigations highlight the significant influence and positive effect of a preageing treatment at lower temperatures on the subsequent artificial ageing treatment.

Analysis of Inclusions and Impurities Present in Typical HPDC, Stamping and Extrusion Alloys Produced with Different Scrap Levels

Analysis of Inclusions and Impurities Present in Typical HPDC, Stamping and Extrusion Alloys Produced with Different Scrap Levels

Research progress and future prospects on high speed extrudable magnesium alloys: A review

Magnesium (Mg) and its alloys, as the lightest metal structural materials, are significantly attractive for lightweight applications. However, the extrudability of commercial Mg alloys is obviously poor compared with Al alloys, which has greatly restricted their widespread application so far. To further expand the industry uptake of Mg alloy extrusion components, development of the low-cost, high speed extrudable Mg alloys with good mechanical performance is strongly desired. In this review, the factors determining the extrudability of Mg alloys are critically analysed. Besides, recent research highlights on high speed extrudable Mg alloys are systematically reviewed from the perspective of the alloying systems, specifically focusing on Mg–Al, Mg–Zn, Mg–Sn, Mg–Bi and Mg–RE based alloys. Furthermore, the new alloy design concepts and novel extrusion processing routes are critically analysed and summarized, and also the recommendations for future research prospects for high speed extrudable Mg alloys are also suggested. We hope this review will inspire new ideas on both composition design and technology innovation for developing high speed extrudable Mg alloys with excellent strength-ductility synergy.

Mechanical responses and microstructure evolution of a 7A09 aluminum alloy extrusion profile during novel stretch bending

This paper proposes a new stretch bending approach for aluminum alloy extrusion profiles based on a novel pre-hardening forming (PHF) process. Tensile tests were carried out to examine the flow behavior and mechanical responses of a 7A09 extrusion profile in PHF process. Microstructure evolution was investigated through X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), electron backscatter diffraction (EBSD), and small angle X-ray scattering (SAXS). It is interesting to find that the yield stress at 200 °C was higher than that at 185 °C. The quantitative analysis revealed that the higher volume fraction of precipitates (200 °C) played a greater role than the refinement of precipitate sizes (185 °C) in precipitation strengthening mechanism, thereby causing an enhanced hardening effect. This phenomenon indicated that there was a preferred temperature zone for the precipitation behavior in PHF process, and it also explained the lower yield stress at 185 °C than that at 200 °C. Additionally, similar results were also observed in strength of the warm-deformed alloys. The optimal strength (σ/σ0.2=589/517 MPa) can be achieved at 200 °C without subsequent heat treatment, which exceeded the typical strength of 7A09-T6 extrusion. The primary strengthening mechanisms in PHF process were strain hardening and precipitation strengthening, and the warm forming procedure caused a hardening effect, rather than a softening impact as in traditional warm/hot forming procedures.

Grain refinement and strengthening mechanism of AZ31 magnesium alloy formed by pre-upsetting alternating forward extrusion

The pre-upsetting deformation process was added before the alternating forward extrusion forming, which can significantly refine the grains and improve the mechanical properties while reducing the load. The effects of 14%, 25%, 36% pre-upsetting deformation on the microstructure and mechanical properties of AZ31 magnesium alloy were investigated. The results show that the pre-upsetting alternating forward extrusion (UAFE) process can achieve significant grain refinement from 31.1 µm to 2.9–3.5 µm. With the increase of pre-upsetting deformation, the elongation at break tends to decrease and the tensile strength tends to increase. The comprehensive mechanical properties of U2AFE are the best, the yield strength and tensile strength are 203.1 MPa and 299.0 MPa respectively, and the elongation at break is 12.5%. The enhancement of the pre-upsetting deformation process not only makes the basal plane of grains in the billet randomly distributed and weakens the basal plane texture, but also stores a large amount of strain energy and dislocation inside the billet, which accelerates the subsequent continuous dynamic recrystallization (CDRX) process of alternating extrusion. This provides scientific guidance and technical support for the research of high-performance magnesium alloy extrusion forming technology.

Improved mechanical properties of high-speed extruded BA53 alloy through long-range water-cooling system

A recently developed Mg–5Bi–3Al (BA53, wt%) alloy exhibited remarkable extrudability despite its high alloying content. However, when subjected to high-speed extrusion with a die exit speed of 67 m/min, grain coarsening of recrystallized grains occurs, increasing their size from 12.1 to 26.4 μm due to excessive heat generation during extrusion. Herein, a long-range water-cooling system is installed immediately after the extrusion die to mitigate grain coarsening and attain finer grains in the high-speed extruded alloy. The results demonstrate that the use of the cooling system leads to a significant reduction in the average grain size (from 26.4 to 15.7 μm) of the BA53 alloy extruded at high speed. Furthermore, grain refinement led to notable increases in the ultimate tensile strength (from 255 to 276 MPa) and elongation (from 7.5% to 8.6%) of the alloy. These enhancements in strength and elongation are primarily attributed to the enhanced grain-boundary hardening effect and suppression of twinning during tension, both of which are consequences of grain refinement. This study underscores the effectiveness of a long-range water-cooling system, comprising water spraying over a length of 2 m, in achieving grain refinement during high-speed extrusion of the BA53 alloy and improving both the strength and ductility of the alloy after high-speed extrusion.

Achieving low tension-compression yield asymmetry and ultrahigh strength in Mg–1Al–1Ca–0.2Mn (wt%) alloy via sub-micron grain refinement

Traditional low-alloyed Mg–Al–Ca–Mn extrusion alloys always show a low strength and a high tension-compression yield asymmetry. In the present work, Mg–1Al–1Ca–0.2Mn (AXM1102, wt.%) alloys were extruded at 150–350 °C to produce different grain structure and mechanical properties. It is shown that AXM1102-150 (extruded at 150 °C) sample exhibits superhigh strength in both tension and compression, which exhibited a yield strength (YS) of 428 MPa in tension and 416 MPa in compression. Namely, ultrahigh strength and low tension-compression yield asymmetry were both obtained. The ultrahigh strength was found to be ascribed to the ultra-fine dynamically recrystallized (DRXed) grains (0.47 μm) together with grain boundary co-segregation of Ca and Al atoms. Submicron DRXed grains accounts for the improved tension-compression yield asymmetry through suppressing {10-12} twining during compression. Additionally, the discontinuous yielding was detected during tension of AXM1102-150 alloy, which is potentially related with the high energy barrier required for dislocation emission caused by grain boundary co-segregation of Al and Ca atoms. Once the tensile stress reaches the peak value, the mobile dislocation density increases immediately, thus the tensile stress-strain behavior of the AXM1102-150 alloy is dominated by strain softening. The results indicate that low-alloyed Mg–Al–Ca–Mn alloys demonstrate tremendous potential as next generation ultrahigh-strength and low tension-compression yield asymmetry wrought Mg alloys.

Aluminum alloy extrusion scheme and model with reduction of basis metal waste

Aluminum alloy extrusion scheme and model with reduction of basis metal waste

Effect of assembling clearance on welding characteristics of laser-MIG hybrid welding for aluminum alloy extrusions

Effect of assembling clearance on welding characteristics of laser-MIG hybrid welding for aluminum alloy extrusions

Development of low rare-earth containing magnesium alloy with high strength-ductility synergy by engineering nano-spaced lamellae

Conventional Mg-RE-based alloys containing a high content of RE solutes can generate high strength, but there is often low ductility. Herein, we reported a low RE alloying Mg–5Er-1Nd-1Zn-0.2Zr extrusion alloy with only 6 wt% RE addition, showing a high strength-ductility synergy, such as a yield strength of ∼380 MPa and an elongation of ∼12.5 %), which is superior to the majority of traditional Mg-RE-based wrought alloys with at least 12 wt% RE addition. Nano-spaced lamellae was formed in the α-Mg matrix during extrusion, such as stacking faults (SFs) evolved in dynamically recrystallized (DRXed) grains and the 14H long-period stacking-ordered (LPSO) phase developed in unDRXed grains as a result of dynamical solute partitioning during extrusion. And this alloy characterizes a high proportion (∼70 %) of elongated unDRXed grains with a strong basal texture. Thus, high strength is mostly related to SFs/LPSO lamellae strengthening and texture hardening, instead of the commonly accepted refinement strengthening and precipitation hardening in those of high RE containing Mg alloys. While high ductility is heavily dependent on SFs/LPSO lamellae to trigger strain hardening and <c + a> dislocations glide, independent of fine grains as in traditional Mg alloys with high elongation. The findings give an insight into the development of high-performance Mg wrought alloys with a high strength-ductility synergy.

Numerical investigation of the surface recrystallization during the extrusion of a AA6082 aluminum alloy under different process conditions

Numerical investigation of the surface recrystallization during the extrusion of a AA6082 aluminum alloy under different process conditions

Microstructure and properties of laser-MIG hybrid welded joints for aluminum alloy extrusions with different gap sizes

Microstructure and properties of laser-MIG hybrid welded joints for aluminum alloy extrusions with different gap sizes

Effect of ram speed on surface quality and mechanical properties during extrusion of AA2024 alloy

AA2024 aluminium alloys are extensively used for aerospace applications that demand higher strength requirements. However, the productivity during extrusion of AA2024 is highly limited and is about one tenth in comparison with soft alloys such as AA6063. In the present work, numerical simulation studies were carried out to extrude solid bar of AA2024 alloy under different processing conditions i.e billet preheat, ramspeed. For simulation studies, the limits of extrusion being selected are extrusion ratio and product exit temperature. From the studies, it was observed that higher preheat temperatures have resulted in higher product exit temperatures. Subsequently, press trial on 1400 Ton extrusion press was conducted to correlate with simulation results and extrudates were characterized to observe the effect of ram speed and extrusion load on surface quality. Increase in ram speed during extrusion has resulted in increase in mechanical properties. However, at a ram speed higher than 1.5 mm/s, surface cracks appeared on the sample and safe limiting ramspeed was 1.5 mm/s.

Optimization of Deformation Behaviors during Continuous Forming Extrusion of C18150 Copper Alloy through Response Surface Methodology

Continuous extrusion (CE) is a method of creating endless profiles of high-quality products of dimensional accurateness, high productivity, and excellent material properties. The main objective of this study is to investigate the influence of CE input process parameters on optimal overall extrusion load requirement and effective stress induced. The input parameters considered were extrusion driving wheel speed, feed metal temperature, tool temperature, and factor of friction proceeding. Numerical simulations of a copper alloy (C18150) were carried out using DEFORM-3D to investigate the impact of the input variables on total load and effective stresses. A mathematical model based on response surface methodology (RSM) was developed for optimized results. The optimized parameters in terms of wheel extrusion velocities, feedstock temperatures, tool temperatures, and friction factors expressed. The ANOVA test was performed to assess the suitability and appropriateness of the model. Using RSM, the optimal load value of 408.167 kN and effective stress of 1241.0 MPa were achieved within the composite preference of 1.0. A load of 408.167 kN had been obtained if the velocity of the wheel, temperatures of feedstock, tool temperatures, and factors of friction are 4 rpm, 500°C, 400°C, and 0.85, respectively. The minimum effective stress of 1241.0 MPa is induced in the feedstock due to the CE process if the velocity of the wheel, temperature of the feedstock, die temperature, and frictional factor were 4 rpm, 500°C, 400°C, and 0.95, respectively.

Mechanical Properties of 6061 Aluminum Alloy under Cyclic Tensile Loading

During the service process of an aluminum alloy structure, its complex deformation zone experiences repeated loading problems such as repeated tension, compression, bending and reverse bending. At the same time, the cyclic loading and heat treatment process also have a certain impact on the mechanical properties of aluminum alloy extruded tubes. Therefore, the study of heat treatment process parameters has important engineering and practical value for the mechanical properties of aluminum alloy extrusion tubes under cyclic loading conditions. The experiment takes 6061-T6 aluminum alloy extruded tubes as the research objects. In the study, heat treatment and cyclic tensile tests were carried out on 26 aluminum alloy specimens to study the effects of different heat treatment parameters (such as heating temperature, holding time, and cooling method) on the stress–strain hysteresis curves, stress characteristics, hysteretic energy, skeleton curves and failure characteristics of the alloy under the same loading system. In addition, different cyclic tensile tests were carried out on 20 aluminum alloy samples without secondary heat treatment to discuss the effects of different cyclic loading regimes on the mechanical properties of the alloy. The research results indicate that the effect of heating temperature on the cyclic loading performance of the alloy is greater than that of the holding time, and the effect of the cooling method on the cyclic loading performance of the alloy is not obvious. A cyclic tensile loading regime has a significant impact on the strength, elongation and hysteresis energy of the alloy. The hysteretic behavior of the alloy during cyclic tensile loading depends on the applied stress level and loading history. As the number of cycles increases, the shape of the hysteresis curve tends to be stable, but there is no monotonic relationship between the number of cycles loaded and the hysteresis energy.