Friction Stir Back Extrusion Research Articles

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.

Microstructure, mechanical, electrical and wear properties of friction stir back extruded copper-6 vol.%Ti2SnC composite material

ABSTRACT This study investigates the impact of extrusion speed on the microstructure, mechanical and electrical properties, and wear resistance of friction stir back extruded Cu-6 vol.% Ti2SnC composite. The findings reveal that severe plastic deformation and heat generated during friction stir back extrusion (FSBE) of Copper-6 vol.% Ti2SnC composite prevented the formation of inter metallics at the particle-matrix interface and resulted in improved bonding. Increasing the speed from 45 to 85 mm/min reduced the maximum plastic strain from 65 to 48 and increased the strain gradient from the surface to the centre of the wire sample. The average grain size decreased from 7.6 ± 0.3 to 3.6 ± 0.2 µm and the average hardness increased from 121.59 ± 8.87 to 130.06 ± 9.95 HV. The yield strength, ultimate tensile strength and elongation decreased by 5.6%, 24% and 12.7% respectively. Wires obtained at the reduced speed of 45 mm/min exhibited an increase of 13% and 26% in electrical conductivity and wear resistance respectively relative to those of the copper matrix material. Analysis of results in the light of a few models indicate that they are in conformity with the results of some of them.

Numerical Analysis of Process Parameters and Tool Geometry in Friction Stir Back Extrusion of Pure Aluminum

Friction Stir Back Extrusion (FSBE) is an innovative process that offers efficient aluminum waste recycling and wire production. This process boasts economic and environmental advantages, as it requires minimal energy compared to traditional recycling casting methods. The objective of this study is to analyze the impact of process parameters using a Finite Element Method (FEM) model based on thermo-mechanical 3D Lagrangian. The study focuses on an AA1080 aluminum alloy and employs different geometric tools, including hole extrusion diameters of 4 mm and 8 mm, as well as a shoulder with two distinct angles of 10° and 15°. Furthermore, variations in several process parameters, such as a constant axial feed rate of 0.5 and 1 mm/min and a constant rotational speed of the die set at 100, 300, and 500 rpm, are considered. The simulation plan encompasses a total of 24 combinations of these parameters to identify the optimal conditions for chips extrusion. Subsequently, the obtained results were analyzed using Design of Experiments (DoE) analysis to assess the influence of each parameter on peak force, torque, and temperature during the process.

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.

Effect of friction stir back extrusion on direction-dependent properties of gradient AZ91-bioactive glass composite rod

This research investigated the microstructure, mechanical properties, and corrosion resistance of friction stir back extruded AZ91-bioactive glass composites in parallel and perpendicular directions to the extrusion direction. The results showed that small grains are observed on the lateral surface, especially where bioactive glass is more prevalent. The grain size increases toward the center of the composite rod. The grain size and relative content of the β-Mg17Al12 phase shift from 30.2 ± 2.3 μm and 0.45 on the lateral surface of the composite rod to 37.4 ± 3.2 μm and 0.12 at the center of the composite rod, respectively. The corrosion resistance and hardness of the lateral surface area of the composite rod are 23 and 26%, respectively, higher than the corrosion resistance and hardness of the transverse surface. The lateral surface of the composite rod shows 74% higher corrosion resistance than the lateral surface of friction stir back extrusion processed wire without bioactive glass particles.

Evaluation of AZ91-bioactive glass composites produced by the friction stir back extrusion technique

In the present study, the effects of bioactive glass (64SiO2-31CaO-5P2O5) reinforcement on the microstructure, mechanical properties, and in-vitro corrosion characteristics of AZ91-bioactive glass composite wire, produced via friction stir back extrusion (FSBE), were investigated. The findings reveal that the bioactive glass reinforcement phase, exhibiting a gradient distribution in the AZ91 matrix and the α-Mg and β-Mg17Al12 phases, predominantly appear in the extruded samples. Additionally, a higher rotational speed during FSBE reduces bioactive glass powder agglomeration within the AZ91 matrix. The optimal yield strength, ultimate tensile strength, and corrosion resistance were observed in the FSBE-processed composite containing 5 vol% bioactive glass. It was revealed that employing a rotational speed of 1200 rpm and an extrusion speed of 30 mm/min during FSBE on as-cast AZ91 alloy with 5 vol% bioactive glass led to an 86 % enhancement in corrosion resistance in simulated body fluid (SBF) compared to the as-cast alloy. Incorporating 5 vol% bioactive glass into the homogenized AZ91 alloy increased corrosion resistance by 98 %. Moreover, raising the rotational speed from 800 to 1200 rpm resulted in a 24 % increase in corrosion resistance, reaching a 0.0427 mm/year rate.

The microstructure and mechanical and corrosion properties of Mg matrix composites reinforced with bioactive glass: The combined effect of bioactive glass content and extrusion speed

This paper studies the influence of 64SiO2–31CaO–5P2O5 bioactive glass particles on the microstructure, and mechanical and corrosion characteristics of AZ91-bioactive glass composite wires fabricated by friction stir back extrusion (FSBE). According to the findings, the extruded composite mostly includes the α-Mg and β-Mg17Al12 phase, as well as the bioactive glass reinforcing phase with a gradient distribution in the AZ91 matrix. The hardness of the FSBE-processed composites increased to 81.32 HV with increasing bioactive glass phase content from 1 to 5 vol % and extrusion speed from 20 to 40 mm/min. In the FSBE-processed composite with 5 vol % bioactive glass particles, the maximum yield strength, ultimate tensile strength, and corrosion resistance of 253.34 ± 9.31 MPa, 298.73 ± 8.95 MPa, and 0.0457 mm/year were obtained, respectively. Compared to AZ91 alloy the polarization resistance in the simulated body fluid solution of AZ91-bioactive glass composite increased and reached 298.21 Ω.cm2. The use of composite samples in circumstances requiring biodegradable implants seems to be promising.

Effect of friction stir back extrusion rotational speed on microstructure, mechanical properties, and corrosion behaviour of AZ91-Ca alloy

In this study, the effect of severe plastic deformation via friction stir back extrusion on microstructure, mechanical properties, and corrosion behavior of AZ91-Ca alloy were investigated. The results show that due to the high temperature during the process at a rotation speed of 1200 rpm, all the β-Mg17Al12, and Al2Ca phases are dissolved, and next to the manganese-rich compounds, re-precipitation of the β-Mg17Al12 and Al2Ca phases is observed. Also, increasing the rotation speed from 800 to 1200 rpm increases the accumulated strain from 0.186 to 0.351. With decreasing rotational speed from 1200 to 800 rpm, the texture parameter of the basal and prismatic planes is reduced, and on the contrary, the texture parameter of the pyramidal planes is increased. The ultimate tensile strength value increases from 332.14 ± 8.71 MPa to 375.13 ± 7.45 MPa by decreasing the rotational speed from 1200 to 800 rpm. The ultimate tensile strength, yield strength, elongation percent, and corrosion resistance in the sample processed at 800 rpm increased by 78, 49, and 32%, respectively, when compared to the as-cast base metal.

Fabrication of a gradient AZ91-bioactive glass composite with good biodegradability

This study used friction stir-back extrusion to fabricate the AZ91 + 3 wt% bioactive glass gradient composite wire. The microstructure, mechanical properties, and corrosion resistance of a material in a simulated body fluid were investigated. Three 2-mm diameter holes with varying hole patterns were drilled in the cross-section of the AZ91 rod to apply 3 wt % bioactive glass to the AZ91 matrix. The results demonstrated that the hole pattern strongly influenced the material's flow in the extruded wire's cross-section. By increasing the distance between the center of the initial rod and the center of the holes, a higher temperature and more uniform distribution of plastic strain are formed during friction stir back extrusion, resulting in uniform distribution of bioactive glass particles and α + β eutectic structure near the surface of composite wires. Introducing bioactive glass particles into the zone near the surface of the AZ91 rod results in the formation of a uniform distribution of bioactive glass particles near the surface and their absence in the central zone of the composite wire. A higher amount of discontinuous β-Mg17Al12 phase and α + β eutectic formed at the grain boundaries by increasing the temperature and plastic strain during friction stir-back extrusion. The crystallographic texture of the AZ91 rod changed from prismatic to basal and pyramidal due to the friction stir-back extrusion method. A gradient AZ91-bioactive glass composite wire with ultimate tensile strength, yield strength, elongation, and corrosion resistance 58, 64, 62, and 34%, respectively, greater than AZ91 as-cat rod can be produced by inserting bioactive glass powder using a hole drilling method and applying a friction stir back extrusion process.

Investigation of microstructure and corrosion behavior of AZ91/64SiO2-31CaO-5P2O5 composite wire fabricated by friction stir back extrusion

In this study, the AZ91-bioactive glass surface composite wires were created using a unique method called friction stir back extrusion (FSBE). The microstructure, mechanical properties, and corrosion resistance of FSBE-processed wires were studied. The results show that by applying the FSBE process, the amount of β-Mg17Al12 phase decreased compared to the as-cast AZ91 rod. Also, by increasing rotational speed during FSBE, the distribution of bioactive glass powder in the AZ91 matrix become more homogenous, and gradient AZ91 matrix composite is fabricated at a rotational speed of 1200 rev/min. By increasing temperature and plastic strain during FSBE at high rotational speed, the higher amount of discontinuous β-Mg17Al12 phase and α + β eutectic formed in the grain boundaries. By inserting bioactive glass powder using a hole drilling method and applying the FSBE process, a gradient AZ91-bioactive glass composite wire with ultimate tensile strength, yield strength, elongation, and corrosion resistance of 58, 64, 62, and 34 % higher than AZ91 as-cat rod can be achieved. Also, the corrosion resistance of gradient AZ91 matrix composite at simulated body fluid (SBF) increased 48 % compared to as-cast AZ91 base metal.

Fabrication of new gradient AZ91-bioactive glass composite using friction stir back extrusion

This study investigated the microstructure, mechanical characteristics, and in vitro corrosion behavior of gradient AZ91-bioactive glass composite wire fabricated by friction stir back extrusion. The results showed that by decreasing the extrusion speed from 40 to 20 mm/min, the distribution factor of bioactive glass increased from 0.31 ± 0.04–0.45 ± 0.07, and more homogenous grain size was formed at the surface and center zone of the composite wire. Under the influence of heat and plastic deformation during friction stir back extrusion, despite the formation of the β-phase in separate islands, the α + β eutectic phase was also formed in the composite wire. In composite wire processed with a rotational speed of 800 rpm and extrusion speed of 20 mm/min, a gradient distribution of bioactive glass was formed in the cross section of the wire. Compared to an as-cast AZ91 alloy, friction stir back extrusion conducted at a rotational speed of 800 rpm and an extrusion speed of 20 mm/min resulted in a 44% increase in corrosion resistance in simulated body fluid (SBF).

Microstructures and properties of copper matrix composite wires reinforced with Ti2SnC particles

ABSTRACT This study investigates the fabrication of copper matrix composite reinforced with 8 wt-% of the Ti2SnC phase using friction stir-back extrusion. It explores the effect of rotational speed on the microstructure and properties of Cu–Ti2SnC wire composites. The results showed that the grain size of the composite increased from 3.5 ± 0.6 to 5.7 ± 0.5 µm as the rotation speed increased from 400 to 1000 rev min−1. With the addition of the Ti2SnC phase, the yield and ultimate tensile strength increased by 178% and 33%, respectively. In addition, although the electrical conductivity decreased by 25% by adding 8 wt-% of reinforcement, the electric conductivity of composite wire increased by 19% with the increase of the rotation speed from 400 to 1000 rev min−1.

Effects of Ti2SnC MAX phase reinforcement content on the properties of copper matrix composite produced by friction stir back extrusion process

In this present work, the effect of Ti2SnC content on the microstructure, mechanical, electrical and wear properties of friction stir back extrusion (FSBE) processed Cu–Ti2SnC composite wire was investigated. The FSBE process was performed on copper matrix composite with 0–30 vol% of Ti2SnC reinforcement. The results show that by increasing the content of the Ti2SnC phase the hardness of the composite increased and reached 280.51 HV for composite containing 30 vol% Ti2SnC phases. The proper interface bonding was obtained in the composite containing 1 and 5 vol% Ti2SnC phases. The highest yield strength, ultimate tensile strength and wear resistance were obtained in the composite containing 5 vol% Ti2SnC phases due to the proper interface bonding. Also, the highest electrical conductivity (95.67% IASC) was obtained in a composite containing 1 vol% Ti2SnC phases. By increasing Ti2SnC phases higher than 5 vol% discontinuities between the Ti2SnC phase particles and the Cu matrix increased and result in decreasing strength and electrical conductivity of copper matrix composite.

Effects of Ti2SnC MAX Phase on Microstructure, Mechanical, Electrical, and Wear Properties of Stir‐Extruded Copper Matrix Composite

Herein, the effect of Ti2SnC MAX phase reinforcement and friction stir back extrusion (FSBE) parameters on the microstructure, mechanical, electrical, and tribological behavior of Cu‐Ti2SnC composite is investigated. The results indicate that, depending on the rotational speed of the extrusion process, an equiaxed grain microstructure with a uniform distribution of reinforcing particles is formed after the extrusion process. Comparing the extruded samples to the unprocessed samples reveals a larger grain size after extrusion. The absence of MAX phase particles causes the formation of finer grain size in the extruded sample. Under the influence of heat and plastic strain, a reactive layer containing a solid solution of Cu(Sn) or Cu3Sn compounds is formed at the interface of the particle and the copper matrix. By performing the extrusion process, the reactive layer at the interface is broken and scattered on the copper matrix. Furthermore, by applying MAX phase reinforcing particles and performing the extrusion process, the copper matrix's hardness, tensile strength, and wear resistance increase by 128, 99, and 84%, respectively. The five vol% Ti2SnC MAX phases in the extruded copper matrix composite wire results in 7.3% reduction in electrical conductivity.

Submerged Friction Stir Back Extrusion of AZ31 Magnesium Alloy

Friction Stir Back Extrusion (FSBE) is a new grade of severe plastic deformation process capable of producing metallic tubular geometries that exhibit ultrafine grain structure and superior mechanical properties. FSBE of tubular sections provide opportunities for producing lightweight rigid structures for the automotive, aerospace and construction industries. This research investigates the effect of submerging conditions (in water at 25 °C and 2 °C) for Magnesium AZ31-B tubes on the grain size, mechanical properties, temperature history and power consumption. Submerged FSBE is compared to FSBE in air at fixed process parameters of 90 mm/min and 2000 rpm. It is shown that the impact of submerging is statistically insignificant in terms of the mechanical properties, ultimate tensile strength and percent elongation, of the produced tubes according to the conducted t-tests. On the other hand, the optical microscopy results indicated finer grains at the inner wall of the seamless tubes for FSBE in air and underwater FSBE at 25 °C when compared to underwater FSBE at 2 °C.

Unraveling the role of micro-arc oxidation process factors on the corrosion resistance of magnesium alloy microtubes

This study employed Micro Arc Oxidation (MAO) to coat ceramic-based coating on fabricated microtubes for biological applications. Although there is information on the MAO coating of sheets and plates, there is relatively little technical information on applying the MAO method to tubes. The impact of crucial MAO process parameters such as current density, inter-work distance, and coating time on the microstructure, porosity, and corrosion resistance of MAO coating deposit on friction stir back extrusion magnesium alloy microtube was studied. The central composite rotatable design was used to conduct experimental runs involving three parameters, modified at three distinct levels. According to the design matrix, cross-sectional images of MAO-coated magnesium microtube were used to quantify interface microstructure . The porosity and corrosion resistance of coated microtubes were tested in a simulated body fluid environment, and the results were connected with process variables using an empirical connection. The usage of MAO coating has been found to have promising outcomes in extending life, lowering corrosion degradation rates, and improving mechanical integrity.

A comprehensive multi-level circular economy assessment framework

With several industries shifting from the conventional liner to circular economy (CE) models, it became necessary to develop standard tools to assess the circularity of different products and processes to facilitate this transition. The conducted thorough literature review presented in this paper concludes that most circularity assessment tools lack comprehensiveness and objectivity due to complexities that arise from the quantification processes of qualitative data, the extensive use of linguistic terms, and the difficulty in combining more than one indicator in case of similarity, dependency, or both. Thus, this paper aims to develop a comprehensive CE assessment framework that is capable of assessing the circularity of processes and products from a wide range of industries and sectors. The framework developed enables a comprehensive assessment by incorporating a step-by-step indicators selection procedure that covers the micro, meso, and macro CE levels of implementation. Also, the framework is capable of dealing with quantitative as well as qualitative indicators while limiting uncertainties associated with linguistic terms. This is achieved by incorporating fuzzy logic into the assessment framework. Moreover, it offers flexibility in selecting between subjective and objective assessment methods through the integration of several Multi-Criteria Decision-Making (MCDM) methods that are also used to rank the assessed processes or products based on their circularity. An example was presented to validate the applicability of the framework and to guide users on to how to draw conclusions about the circularity of the assessed objects from the scores obtained. In the example, the circularity of Friction Stir Back Extrusion (FSBE) is assessed against the circularity of conventional extrusion. FSBE achieved a relative circularity score of 69.23% compared to 30.77% for conventional extrusion. In future, it is encouraged that policymakers and experts collect and build databases of indicators of their own fields to ease the circularity assessment and enhance its consistency.

Harnessing friction stir back extrusion process to fabricate microtubes from as-cast Mg–4Zn–0.7Zr-1.6RE magnesium alloy

Friction Stir Back Extrusion (FSBE) is a novel manufacturing process widely used to produce lightweight tubes with superior mechanical properties. This work aims to establish the optimum process parameters of the FSBE method to fabricate flaw-free small-scale magnesium microtubes from as-cast Mg-Zn-Zr-Re magnesium alloy. FSBE experimental trials in the light of the Taguchi optimization were attempted to optimize and develop relationships that can link the crucial process parameters, namely tool rotational rate, feed rate, and billet preheating temperature of the FSBE process on the microstructural alterations, microhardness, and corrosion resistance characteristics. The results suggest that the FSBE parameters, especially the tool feed rate, have a crucial influence on the performance attributes of microtubes. Additionally, it is evident that both the tool rotation rate and feed rate significantly affect the formation of dynamically recrystallized fraction (DRX) of the stir zone. The stir zone has achieved a higher density of fine recrystallized grains than the base metal region, which subsequently led to a spike in the microhardness values of this zone. This study has determined that the FSBE technique significantly enhanced the corrosion degradation resistance of microtubes as compared with cast material. The optimal FSBE parameters such as tool rotational rate of 1440 rpm, feed rate of 20 mm min−1, and billet preheating temperature of 100 °C have offered microtubes with the highest microhardness and lowest corrosion degradation rate.

Decisive influence of critical process parameters on the microstructure and tensile properties of friction stir back extruded magnesium alloy tubes

Friction Stir Back Extrusion (FSBE) is evolving as a novel extrusion process for producing high strength ultrafine-grained tubes from a range of metallic alloys. This investigation focuses on developing a high-fidelity experimental methodology to control the critical process parameters of the FSBE process for manufacturing high strength ZE41 magnesium alloy tubes. The crucial parameters of FSBE required to manufacture highly reliable ZE41 tubes were determined with solid evidence obtained through a wide range of thorough experimental trials on ZE41 magnesium round rods. The metallurgical characterisation was performed at key regions across the tubes obtained using the ideal process conditions to understand the influence of FSBE process parameters on the microstructural formation. Mechanical properties of the tubes were evaluated and found that the tubes produced at optimum conditions have achieved high tensile and hoop strengths. The microstructure-mechanical property correlation confirmed that the FSBE process driven with the controlled process parameters enable to produce defect-free high strength ZE41 magnesium tubes with a significant enhancement in grain refinement.

Manufacturing of gradient Al/SiC composite wire by friction stir back extrusion

In the current research, the friction stir back extrusion (FSBE) process as a novel method was used to fabricate the gradient AA6063/SiC composite wires. The scanning electron microscopy equipped with EDS analysis was utilized. To investigate mechanical properties, hardness and tensile tests were used. The results revealed that the distribution of SiC particles in the matrix is dependent on volume fraction. Particle distribution of AA6063/6% SiC sample was uniform while that of AA6063/12% SiC and AA6063/18% SiC was gradient. Gradient distribution had an important effect on the mechanical properties of composites. The tensile strength of all composite samples was improved so that the tensile strength of the Al/12% SiC composite became 2 times greater than that of the base material. Interestingly, the elongation of Al/12% SiC composite slightly increased compared to the base metal. This was due to a unique gradient distribution of silicon carbide particles in the aluminum matrix. Generally, the presence of the SiC particles caused to significant improvement of mechanical properties compared to the base metal.