Effect Of Extrusion Speed Research Articles

Microstructure and mechanical properties of a low-alloyed Mg–Zn–Al–Ca alloy: Effect of extrusion speed

A low-alloyed Mg-1.2Zn-0.6Al-0.1Ca (wt.%) alloy was extruded at 200 °C with different ram speeds (0.5–4.0 mm/s), and the microstructure and mechanical properties were studied systematically. Heterostructures with fine dynamic recrystallized (DRXed) grains and coarse unDRXed grains were achieved at lower ram speeds of 0.5 mm/s and 1.0 mm/s, and fully-DRXed microstructure was attained at 4.0 mm/s. Increasing the extrusion speed resulted in an increase in DRXed grain size from 0.9 μm to 3.8 μm, and a transformation of the DRXed texture component from <10 to 10>−<11–20> to a new orientation that deviated by approximately 14°. The sample extruded at 0.5 mm/s presented an excellent tensile yield strength (TYS) of 369 MPa along with a 7.8% elongation, which was mainly due to the high hetero-deformation induced (HDI) strengthening provided by its heterostructures. Increasing ram speed resulted in an improved elongation despite a decreased TYS. The reasons for the decreased strength with increasing extrusion speed were mainly associated with grain growth, reduced dislocation density and weakened HDI strengthening. The reasons for the improved ductility with increasing extrusion speed were largely due to the increased DRXed grains fraction with soft orientations.

Effect of extrusion speed on properties of Cu−5vol.%Ti2SnC composite wire fabricated by friction stir back extrusion process

The effect of axial traverse speed of friction stir back extrusion (FSBE) process on the microstructure, mechanical, electrical, and wear properties of Cu−Ti2SnC composite wire was investigated. The FSBE process was performed on the primary composite made by the powder metallurgy method with 5 vol.% of Ti2SnC MAX phase. The results showed that as the extrusion speed increased, the twins formed in the microstructure increased, the Ti2SnC particles became finer, and the interface of bonding of the MAX phase−Cu matrix improved. The Cu−Ti2SnC composite wire fabricated at the rotational speed of 600 r/min and axial traverse speed of 25 mm/min showed the maximum hardness, yield strength, and ultimate tensile strength of HV 132.7, 278.34 MPa, and 485.15 MPa, respectively. This finding was due to its strong interfacial bonding and fine MAX phase particles. Besides, the larger grain size, the better interface bonding, and the lower the porosity resulted in the highest electrical conductivity of 89.21% (IACS) and least wear rate of 0.0015 mg/m of Cu−Ti2SnC composite wire fabricated at rotational speed of 600 r/min and axial traverse speed of 25 mm/min.

The effect of friction stir-back extrusion speed on Al-Cu-Mg-Li alloy microstructure and corrosion behaviour

ABSTRACT In this study, the effect of extrusion speed on the microstructure and corrosion behaviour of a friction stir-back extruded Al-Cu-Mg alloy containing 0.5 wt.% Li was investigated. Results show that friction stir-back extrusion on an as-cast aluminum alloy with a dendritic microstructure forming finely equiaxed recrystallized grains. With decreasing extrusion speed from 80 to 40 mm/min, the average grain size increases from 6.0 ± 1.2–9.8 ± 3.2 µm. After friction stir-back extrusion, the morphology of the Cu-Mg-rich precipitates has completely changed, and the fine precipitates (0.25-0.42 µm) with a uniform distribution have formed in the microstructure of the extruded wires. With the reduction of the extrusion speed from 80 to 40 mm/min, the accumulated strain in the extruded wires increases from 0.006-0.011. Compared to as-cast alloy, friction stir-back extrusion results in at least 23, 37, and 22% increases in yield strength, tensile strength, and elongation. The minimum corrosion current (1.32 × 10−4 A.cm−2) and corrosion rate (0.003 mm/year) were achieved in the wire extruded at a rotational speed of 800 rpm and an extrusion speed of 60 mm/min.

Investigation of die designs on welding quality and billet material utilisation for multi-container extrusion of wide stiffened aluminium panels

Wide stiffened aluminium panels are extensively used in aerospace, marine, and civil industries due to their light-weight structure and high stiffness. In this paper, a wide stiffened aluminium panel was manufactured using the principle of the multi-container extrusion, and a comparative study was conducted using two different die designs at the same extrusion condition, in which metal flow behaviour, extrusion force, welding quality, and billet material utilisation have been investigated numerically. Additionally, the effect of extrusion speed on the extrusion process was evaluated with the modified design. It was shown that, compared with the initial design, better metal flow behaviour can be obtained in the modified design. Multi-container extrusion greatly reduces the extrusion force, and the modified design results in a more uniform extrusion force for each extrusion container. The total extrusion force for the modified design is slightly higher compared with the initial die design, due to the increased friction in the upper die channels and the second-step welding chamber. Besides, the modified design of the multi-container extrusion can obtain better welding quality evaluated by different welding criteria, and the extrusion speed has a minor effect on the welding quality. The most notable feature is that the modified design greatly improves the material utilisation, which could save 39.5% material compared to the initial design.

Effects of extrusion speed on the formation of bimodal-grained structure and mechanical properties of a Mg-Gd-based alloy

The effect of ram speed ranging from 1 mm/s to 10 mm/s on the microstructure and mechanical properties of a Mg-11Gd-3Y-0.5Nd-Zr (wt%) alloy was investigated using optical microscopy, scanning electron microscopy, electron backscatter diffraction analysis, transmission electron microscopy, hardness testing and uniaxial tensile testing. The results indicate that a bimodal-grained structure composed of elongated deformed grains and fine recrystallized grains is formed in the 1 mm/s extruded sample. Then, the microstructure completely transformed into equiaxed grains when extruded at a speed higher than 5 mm/s, and the recrystallized grains become coarser as the ram speed increasing. Compared with the 5 mm/s and 10 mm/s extruded samples, the 1 mm/s extruded sample exhibits the best strength and ductility. After T5 treatment, the ultimate tensile strength, tensile yield strength and elongation are 456 MPa, 333 MPa and 8.9%, respectively. The excellent mechanical properties are attributed to grain refinement strengthening, texture weakening, bimodal-grained structure and age hardening. The key to form a bimodal-grained structure is to restrict the temperature rise by controlling the extrusion speed. • A simple method to form bimodal-grained structure in Mg-Gd-based alloy is proposed. • The mechanism to form bimodal-grained structure relies on the limited temperature rise by controlling the extrusion speed. • The mechanism for bimodal-grained structure to improve the mechanical properties is discussed.

Effect of extrusion speed on microstructure and mechanical properties of Mg-Al-Ca-Sn alloy

Low-temperature and high-speed extrusion of wrought magnesium alloy is an urgent problem. Mg-2.5Al-2Ca-1Sn alloys were extruded at 260 °C with different ram speeds (2.0, 4.0 and 6.0 mm s)−1. The effects of extrusion speed on the microstructure and mechanical properties of the alloys were systematically investigated. It’s worth noting that all the three extruded alloys were fully dynamic recrystallized (DRXed). With the increase of extrusion speed from 2 mm s−1 to 6 mm s−1, the DRXed grain size are increased from 1.25 μm to 1.94 μm, average second phase particles are augmented from 0.79 μm to 0.89 μm and the volume fraction of second phase increases from 6.4% to 18.6%. All the three extruded samples show excellent comprehensive mechanical properties because of fine grain size, fully recrystallization and homogeneously dispersed second phase particles. The tensile yield strength (TYS) and ultimate tensile strength (UTS) decreased from 285 MPa, 304 MPa to 217 MPa, 264 MPa while the elongation increased from 11.4% to 20% when the ram speed rose from 2.0 mm s−1 to 6.0 mm s−1.

Optimization Design of Cold Extrusion Process Parameters for Multi-Ribs Aluminum Alloy Part

In this paper, the cold extrusion process of aluminum alloy with multi-ribs was studied. The target part is formed by one-step closed cold extrusion. It has the advantages of simple process and high material utilization. The effects of extrusion speed and die corner on forming force and contact stress between billet and die were analyzed. According to the simulation results under different conditions, the reasonable process parameters are selected to obtain the products with full shape and without obvious defects. It can provide an effective reference for the parameter design in the cold extrusion process of this kind of multi-ribs parts.

Effect of extrusion speed on microstructure, mechanical properties and work-hardening of multi-microalloying MgAlCoCrFeNi alloy

In this study, a novel multi-microalloying MgAlCoCrFeNi alloy was extruded at 300°C with different extrusion speeds (0.2, 1, and 2 mm/s). The microstructure evolution, tensile properties and work-hardening behavior of the alloy were studied. Results showed that increasing the extrusion speed could improve the homogeneity of the microstructure, transitioning from a bimodal microstructure (fine recrystallized grains and elongated un-recrystallized grains) at 0.2 and 1 mm/s to a fully recrystallized one at 2 mm/s. The lower extrusion speed could improve the YS of the alloy, which possesses a maximum YS of ~213 MPa at 0.2 mm/s, an increase of ~12% compared to the YS at 2 mm/s, which was mainly attributed to the fine grain strengthening and dislocations (residual dislocations) strengthening. Moreover, the work hardening capacity of the alloy increases with the extrusion speed. As the extrusion speed increases from 0.2 mm/s to 2 mm/s, the work hardening exponent n increased from 0.08 to 0.14, and the work hardening capability Hc increased from 0.31 to 0.52. The analysis results showed that the improvement of work hardening ability was mainly due to the increase of dislocation storage rate caused by grain coarsening.

Effects of extrusion speed and compounds on surface defects in extruded-AA7003 alloy

The defect formation in a rod-shaped AA7003 alloy is carefully treated in the sample extruded at 10 or 20 m min−1 with their structure–property relationships. The <111> + <100> double fibre texture is formed in the extruded rods, but it is altered near the surface of the extrudates due to recrystallisation and recovery, being triggered by the processing heat. This reduces strains at the region, leading to softening of the hardness. Coarse Al9(Mn,Fe)2Si compounds are transported to the die throat with the fragmentation. The agglomeration of compounds occurs near the surface and makes pick-up. Eventually the number of pick-up is much higher in the sample extruded at 20 m min−1.

Effects of Extrusion Speed on the Microstructure and Mechanical Properties of Mg–9Al–0.8Zn–0.9Ca–0.6Y–0.5MM Alloy

The effects of extrusion speed on the microstructure and tensile properties of a recently developed Mg–9Al–0.8Zn–0.9Ca–0.6Y–0.5MM (AZXWMM91100) alloy are investigated by extruding at various ram speeds of 1, 4, 7, 10, and 13 mm/s. Direct extrusion results reveal that numerous small edge cracks form in the sheets extruded at ram speeds between 4 and 10 mm/s, whereas severe hot cracking occurs during extrusion at 13 mm/s. All extruded sheets show a fully recrystallized grain structure containing second-phase particles aligned along the extrusion direction. The average size of the recrystallized grains gradually increases with the increasing ram speed, because a higher extrusion speed generates more deformation heat. However, the size, morphology, amount, and distribution of the second-phase particles are nearly identical in all the extruded sheets. As the ram speed increases from 1 to 10 mm/s, the tensile yield strength of the extruded material decreases from 205 to 125 MPa, which is attributed to the decrease in the grain-boundary hardening effect caused by the grain coarsening. The tensile elongation increases from 13.0% at 1 mm/s to 15.1% at 4 mm/s, and then greatly decreases to 2.9% at 10 mm/s. The drastic ductility degradation of the sheets extruded at the ram speeds larger than 7 mm/s is due to the formation of relatively coarse internal cracks in the material during extrusion.

Effect of extrusion speed on mixed grain microstructure and tensile properties of a Mg-2.9Zn-1.1Ca-0.5Mn nanocomposite reinforced by a low mass fraction of TiCp

In this work, a novel TiC nanoparticle (0.5 wt %) reinforced Mg-2.9Zn-1.1Ca-0.5Mn nanocomposite, with a mixed grain microstructure exhibiting high strength and targeted for biocompatible/structural applications was successfully prepared by ultrasonic assisted semi-solid stirring and extrusion at ultra-slow speeds of 1, 0.1 and 0.01 mm/s. The experimental results revealed that the morphology of the eutectic Ca2Mg6Zn3 phase in the as-cast nanocomposite changed from plate-like to lamellar as a low mass fraction of TiCp was added. Both dynamically recrystallized grains and precipitates were gradually refined with decreasing extrusion speed. The finest recrystallized grains (∼0.46 μm), with a high volume fraction (∼4.3%) of fine precipitates, appeared after extrusion at 0.01 mm/s. The refined grain structure was not only due to dynamic recrystallization, but also the synergistic pinning effects from nano-TiCp as well as precipitated MgZn2 and α-Mn particles. The superior ultimate tensile strength (∼410.3 MPa), yield strength (∼384.5 MPa) and elongation to failure (∼4%) were obtained in the nanocomposite extruded at the slowest speed (0.01 mm/s) and had the potential to serve as a candidate material in orthopaedic applications. The improved strength was mainly related to grain refinement, thermal expansion effects and Orowan strengthening. Grain refinement, in particular, contributed to the largest strengthening increment. High tensile toughness of ∼66.6 KJ mm−3 was achieved for the nanocomposite extruded at a speed of 1 mm/s. Further, it exhibited a high strain hardening rate, θ, at stage IV. The fracture surface exhibited abundant dimples and consistent with high ductility. Remnant coarse Ca2Mg6Zn3 particles acted as crack initiators under high applied stress in tension, leading to structural failure.

Effect of Extrusion Speed on the Microstructures and Density of Compaction Efficiency in Powder Pressing

Powder metallurgy is an effective process of manufacturing near net shape products. It offers many advantages, including high productivity, low production costs less energy consumption and environmental friendship, which is widely concern in powder metallurgy industry. In this paper, the effects of pressing parameters, such as pressing pressure, pressing speed and holding time, on the density of blanking Fe-based amorphous alloys at room temperature are studied. The experimental results show that with the increase of pressure, the density of the blank has just started to increase faster, but the pressing pressure cannot exceed the limit of the die. Accelerating the pressing speed is helpful to increase the density of the compact at the very beginning, but with the pressing speed exceeding one value, the density of the blank decreases. The pressure time is not particularly obvious to the density of the blank, and the general holding time is two minutes.

Effect of process parameters on longitudinal weld seam quality of aluminum alloy profile for an automobile fuel tank protector

The aluminum alloy profile of an automobile fuel tank protector is taken as the research object in this paper, the problem of poor longitudinal weld seam quality is analyzed, and the effect of process parameters on the longitudinal welding quality is studied. The morphology of poor longitudinal weld seam is observed by optical microscopy and scanning electron microscopy. The effects of extrusion speed, extrusion temperature, and billet diameter on the welding quality of the longitudinal weld seam are studied by using K parameters to quantitatively characterize the welding quality. Simulation results show that lower extrusion speed, higher billet temperature and larger billet diameter are beneficial to improve the longitudinal welding quality. The initial extrusion process parameters are adjusted according to the rule of simulation results, and the extrusion test is carried out again. After the adjustment, the longitudinal weld seam quality is obviously improved, which is in accordance with the simulation results.

Effect of extrusion speed and ATO content on rheological properties of plasticised PVC

Rheological properties of antimony trioxide (ATO) modified plasticised PVC were measured at different extrusion speeds (20-100) rpm. The results showed a positive effect of the presence of ATO accompanied with increased extrusion speed, where the rheological properties and gelation grade of PVC have been improved.

Microstructure, mechanical properties and welding quality evaluation of longitudinal welds in hollow magnesium alloy profiles extruded at different ram speeds

Thin-walled and hollow profiles of magnesium alloys have more light-weight advantages. However, longitudinal welds exist inevitably in hollow profiles produced by porthole die extrusion. The welding qualities of the welds have a critical impact on mechanical properties of the profiles. In this paper, hot extrusion experiments of an asymmetrical hollow magnesium alloy profile extruded at different ram speeds were carried out. The effects of extrusion speed on grain structure, second phase particles, texture and mechanical properties of longitudinal welds in hollow profiles were systematically studied. The effects of microstructure and texture on mechanical properties of longitudinal welds were revealed. The fracture morphology and fracture mode of the welds extruded at different ram speeds were analyzed. A method based on K criterion for evaluating the welding quality of magnesium alloy profile in three-dimensional space was proposed. The values of three-dimensional welding quality factor K3D and non-dimensional welding quality factor K⁎ of the hollow magnesium alloy profile were determined respectively. Finally, the welding qualities of longitudinal welds in the hollow magnesium alloy profiles extruded at different ram speeds were evaluated.

Microstructure and mechanical properties of hot extruded Mg-8.89Li-0.96Zn alloy

Abstract The numerical simulation and experiments were conducted to study the hot extrusion of Mg-8.89Li-0.96Zn alloy. The extrusion process was modelled based on finite element method, and the effects of extrusion speed on the distribution of flowing velocity, effective strain rate, and temperature were clarified. Moreover, the extrusion experiments were carried out at varied extrusion speeds, and both the microstructure and mechanical properties of the extruded alloy were examined. The results showed that the flowing velocity, effective strain and temperature increased with the increase of extrusion speed, and the deformation is more severe in the edge of the extruded plate than that in the center. The grain size is smaller and the degree of dynamic recrystallization is higher in the edge zone. With the increase of extrusion speed, the average grain size in the edge zone increased, while the grain size in the center zone firstly decreased and then increased. When the extrusion speed is 0.5 mm/s, the specimen exhibited the best ultimate tensile property and elongation due to its uniform grain size and relatively more recrystallized grains. The hardness increases from the center to the edge due to the decreasing grain size.

Simultaneously improving the strength and ductility of extruded bimodal size SiCp/AZ61 composites: Synergistic effect of micron/nano SiCp and submicron Mg17Al12 precipitates

AZ61 matrix reinforced by micro- and nano-scaled SiC particles fabricated via semisolid stirring assisted ultrasonic vibration was subjected to extruded at different speeds (0.1, 0.5 and 2.5 mm/s) with a constant temperature of 280 ℃. The effect of extrusion speed on the microstructure and tensile properties of the extruded composite was investigated. Grain size, precipitates fraction and texture were found to be greatly affected by the extrusion speed, resulting in tensile properties showing superior strength and ductility as the extrusion speed being of 0.1 mm/s. The improved strength and ductility were ascribed to the synergistic effect of micron/nano SiCp and submicron Mg17Al12 precipitates. The strengthening mechanism of extruded composites was also discussed.

Effect of Extrusion Speed on the Microstructure and Tensile Properties of AZ31 Alloy

The influences of extrusion speed on the microstructure and tensile properties of AZ31 alloy were investigated. The results suggested that the yield and tensile strength of AZ31 alloy decrease but elongation increases with the reduction of extruded speed. High speed extrusion produces fine grains with texture of c -axis perpendicular with extruded direction. The tension deformation is dominated by slip and the formed texture is obstructive for the basal slip, and also the inhomogeneous structure formed at high speed extrusion is harmful to the ductility. Samples extruded at low speed have comparatively homogeneous and coarse microstructure. Twinning provided more tension deformation and the lattice rotation induced by twinning is favorable for the activities of new slip systems, which induced the better ductility of AZ31 alloy.

State-of-the-art of extrusion welding and proposal of a method to evaluate quantitatively welding quality during three-dimensional extrusion process

Aluminum alloy profiles have been widely used in many fields and are attracting more and more attention now. However, for the hollow profiles, longitudinal welding lines occur inevitably and appear on the extruded profiles. Currently, most research in the literatures focuses on the two-dimensional extrusion welding process, which could not reflect the real formation process of a welding line and there are not effective method to evaluate the welding quality during extrusion process. The first part of this work reviews the-state-of-the-art of the extrusion welding in the current literatures. In the second part, a novel method is proposed to evaluate the welding quality during a three-dimensional extrusion process. This method extends the application of the current welding criterion from a two-dimensional extrusion process to a three-dimensional one. By simulating the transient extrusion process of an aluminum tube with Forge-3D, the proposed method is used to evaluate the welding quality of the extrusion process. Based on the method, the effects of extrusion speed and welding chamber on welding quality are investigated quantitatively. With the increasing extrusion speed or decreasing height of welding chamber, the welding quality is getting worse, which is identical to the experimental observations in other publications.

Effects of Extrusion Speed on the Deformation of Copper Using ECAP Based on FEM

Severe plastic deformation is defined as metal forming methods in which a very large strain is imposed to a bulk in order to make an ultra-fine grained metal. ECAP is one of the most effective methods in SPD. The influences of main parameters on deformation include extrusion route, extrusion pass, die corner, friction, extrusion speed and so on. In this investigation, a model of ECAP process has been developed based on FEM and effects of extrusion speed on effective strain, load and effective stress imposed in the copper road are researched. The results of simulation have shown that lower extrusion speed can lead to higher load of top die and effective stress while the effect of extrusion speed on effective strain of copper road is slight.