E ﬀ ect of ECAP die angle and route type on the experimental evolution, crystallographic texture, and mechanical properties of pure magnesium

: In the current study, the e ﬀ ect of equal channel angular pressing parameters such as die route type and die angle were studied. Billets of pure magnesium ( Mg ) were processed successfully through up to 2 - passes of di ﬀ erent routes, A, Bc, and C, using equal channel angular pressing dies with di ﬀ erent internal angles of 90° and 120° at 225°C. The crystallographic texture and microstructural evolution were investigated using electron back - scatter di ﬀ raction. The Vickers microhardness and tensile pro - perties were investigated, analyzed, and linked to the microstructure and crystallographic texture as well. The as - annealed condition revealed relatively coarse equiaxed grains coupled with some extra - elongated grains with average grain size of 6.338 µm. Processing through 2 - passes formed an ultra ﬁ ne grain structure and recrystallized ﬁ ne grains. This decrease in grain size was associated with hard - ness and tensile strength enhancement as compared with the as - annealed Mg counterpart. ECAP processing through the 90° die revealed that 2 - passes of route Bc was more e ﬀ ective in grain re ﬁ nement compared to routes A and C, and it reduced the average grain size by 76.45% compared to the as - annealed counterpart. On the other hand, for the ECAP die with 120°, route A was more e ﬀ ective in grain re ﬁ nement compared to the other routes. Processing through 2 - passes of route C resulted in a stronger texture compared to the other routes with momentous rotation for the texture components. Processing of 2 - A, 2 - Bc, and 2 - C through the 90° - die revealed an increase in the Vickers Hardness ( HV ) of 76.9, 96, and 84.6%, respectively, compared to the AA counterpart. In addition, the tensile ﬁ ndings revealed that the 90° - die resulted in higher ultimate tensile strength coupled with a drop - in ductility compared to the 120° - die. Furthermore, ECAP processing through the 90° - die led to improvement in the ultimate tensile strength by 14.1, 38.4, and 43.75%, respectively, coupled with improving the Mg ductility by 80.9, 73.5, and 47.6% through processing via 2 - A, 2 - Bc, and 2 - C, respectively, compared to the as - annealed counterpart.


Introduction
Magnesium (Mg) alloys are ultralight alloys because of their superior specific strength. Mg alloys' densities are about one-quarter that of steel and two-thirds that of aluminum while still providing adequate strength for a variety of applications [1][2][3]. Furthermore, they exhibit properties such as good recyclability, high-specific stiffness, and great strength-to-weight ratio [4][5][6], which make them desirable materials for transportation industries with automotive and aerospace applications [7][8][9]. Additionally, the replacement of traditional materials in automotive with Mg alloys is a prospective proposal for reducing the emission of carbon dioxide as well as decreasing fuel consumption; it was estimated that reducing a car's weight by 10% results in fuel savings of 5-10% [10]. However, the biggest setback to the implementation of Mg-based alloys is their lack of formability, which hinders their performance in automobile applications.
Mg has a hexagonal close-packed (HCP) crystal structure. This severely limits its ductility as a result of the low number of deformation modes characterizing that crystal structure [11]. The HCP crystal structure's brittleness comes from the fact that the structure's slip systems have substantially different critical resolved shear stresses (CRSS) [5,[12][13][14]. As a direct result, Mg alloys perform poorly when worked on at room temperature using common forming techniques, such as rolling and extrusion, and tend to fail [15]. Hot working provides an escape from the inevitable failure of Mg at room temperature because the heat increases the alloy's deformability. However, the phenomena of dynamic recovery and recrystallization stunt the desirable effects of strain hardening [16][17][18]. A plethora of studies and investigations attempted to engineer Mg alloys free of their well-known shortcomings, offering great strength, ductility [19,20], and better corrosion resistance [20,21]. One such approach was the usage of plastic deformation to control the texture, thus mitigating many of Mg alloys' well-known problems.
In recent years, several investigations were launched into the process parameters of ECAP and its influence on the material behavior. The evolved microstructural and mechanical properties of the ECAPed sample are heavily dependent on the plastic deformation degree and form during processing. Therefore, investigating the strain development phenomena is crucial in the design of the ECAP process. The equivalent strain (ε eq ) can be determined theoretically based on the die geometry by equation (1) [22,33,48]. The strain is mainly affected by the outer corner angle (Ψ), the internal channel angle (ϕ), and the number of passes (N); ECAP is the most effective SPD technique that refines metallic materials' grains the most effective out of all the other SPD approaches and hence improving both the mechanical properties. It is important to mention that the strain extent and distribution in ECAP depends on the rotation of the rod about its longitudinal axis. The common ECAP routes are route A, route Bc, route C, and route B A . Figure 1 illustrates the differences among the different routes. The orientation of the rod in route A remains as is between subsequent passes. However, in route Bc, the rod is rotated 90°between the subsequent passes in the same direction, whereas in route C the sample is rotated 180°(between the subsequent passes) and in route B A the sample is rotated 90°in opposite direction after each ECAP pass [49]. Additionally, research shows that varying the ECAP routes and using multiple passes further influence the grain refinement and are encouraged to provide improved results. The shear plane direction is also heavily affected by these changes and varies throughout the process [50]. Further research shows that the compressive mechanical properties of ECAPed pure Mg at room temperature using an internal channel angle ϕ = 90°and route Bc became worse and fell off after two passes. Analysis concludes that the newly evolved texture was a major cause of that drop-in properties as well as the activation of non-basal slipping systems. Nevertheless, after the fourth pass, the mechanical properties increased because of grain refinement [51].
The effect of ECAP route type and ECAP channel angle were studied in earlier research. Venkatachalam et al. [52] reported that the ECAP process applied on AA2014 through route Bc manifested significant improvement in mechanical properties, hardness, and strength compared to routes A, C, and Ba, which was argued to be a result of the homogenized effective strain in all the planes. Alateyah et al. [28] had investigated the effect of ECAP route types A, Bc, and C on the microstructural and texture evolution and corrosion behavior of the Mg alloy ZK30. They reported that route type Bc is the most effective in grain refinement, and hence, improves the corrosion rate, whereas both routes A and Bc revealed an improved corrosion resistance with nearly identical values. Alateyah et al. [22,26] had developed a full statistical analysis on the effect of ECAP route type, die angle, and number of passes on grain size refinement, cryptographic texture, Vickers hardness (HV), and tensile properties of pure Mg. Gu and Toth [53] reported that route A resulted in a structure with a high density of elongated grains, whereas route Bc resulted in ultrafine grained structure with almost recrystallized equiaxed grains [25]. Illgen et al. [54] reported that processing through the odd number of route C resulted in elongated grains, whereas the even number resulted in almost equiaxed grains.
Unfortunately, there are limited studies of the effect of ECAP on pure Mg because of its poor ductility and deformability. Thus, the objective of this study is to investigate the effect of the most important ECAP parameters such as route type and internal channel angle on the microstructural evolution, cryptographic texture, and mechanical properties of pure Mg. To do so, pure Mg was processed using two ECAP dies with channel angles of 90°and 120°t hrough route A, Bc, and C. Scanning electron microscopy (SEM) equipped with electron back-scatter diffraction (EBSD) was used to analyze the microstructure and texture of Mg billets before and after processing. Vickers microhardness and the tensile properties of the pure Mg billets were investigated and correlated with the microstructure findings.

Materials and methods
In this study, the as-received pure Mg rolled billets were 20 mm in diameter and 500 mm in length. A precisioncutting machine was used to section the ECAP samples from the billets, which were 60 mm in length. Before processing, the samples were annealed at 250°C for 1 h and then furnace cooled. Processing via ECAP was performed through 1-pass and 2-passes (2 P) at 225°C through different routes (A, Bc, C) with a 0.05 mm/s ram speed. To decrease the friction between the ECAPed samples and the inner walls of the die, a graphite-based lubricant was applied before each pass. The ECAP die had a fixed outside arc of curvature of angle 20°(Ψ). However, the angle at which the two channels intersected was made a variable. Two internal channel angles ϕ (90°and 120°) were used as shown in Figure 2, and the samples were processed via both of them. The equivalent strain (ε eq ) imposed by the die channel based on equation (1) was approximately 0.65 per pass. The equal-channel angular pressed samples were sectioned from the center along their longitudinal section (LS) on the normal plane to the die's entrance and parallel to the flow plane (pressing direction). The reference system axes coincide with the ECAP extrusion direction "Y" (ED), the normal direction "Z" (ND), and the transversal direction "X" (TD).
The microstructural and crystallographic textures of the ECAPed Mg under the different studied conditions were investigated using a field emission scanning electron microscope (FESEM, Hitachi, Ltd, Tokyo, Japan) equipped with a NordlysMax2 EBSD detector. EBSD was performed on the TD-ED plane, top surface, using an SU-70 SEM (Hitachi, Ltd, Tokyo, Japan) operating at a typical current of 1.5 nA and 15 kV. Before EBSD, the sample surfaces were prepared by grinding and mechanical polishing down to 1 µm using a tripod polisher and then chemical polishing with colloidal silica (0.05 µm) for 24 h by a BUEHLER Vibrometer (Buehler, Tucson, AZ, USA).
Hardness was evaluated using a Vickers microhardness testing machine. Samples were loaded for 15 s under a load of 0.5 kg. Tensile properties of Mg ECAPed samples were measured using a universal testing machine (Instron 4210, Norwood, MA, USA). Uniaxial tensile tests were conducted with a strain rate of 10 −3 s −1 applied at room temperature. Tensile testing was conducted on samples machined according to the E8 M/ASTM standard and sectioned from the central regions of the ECAPed billets. To ensure the precision of the results, each processing condition was tested using three different samples of that condition.

Microstructure evolution
The grain structures of the as-annealed pure Mg (AA) and all of the ECAPed samples were investigated using EBSD. The inverse pole figures (IPFs) and their band contrast (BC) maps of the AA billet relative to the ND are exhibited in Figure 3. Low-angle grain boundaries (LAGBs) are characterized by having misorientation angles ranging between 3 and 15°, whereas high-angle grain boundaries (HAGBs) are characterized by having misorientation angles that are greater than 15°. LAGBs are shown in red, and HAGBs are shown in black. A side effect of processing via ECAP is the high friction between the die walls and the processed billets, which consequently increases the density of the HAGBs. In addition, the IPFs and BC maps of the ECAPed billets through the 90°and 120°dies are shown in Figures 4 and 5, respectively. Furthermore, Table 1 lists the relevant grain-size data collected from all Mg samples. From Figure 3a it was clear that the microstructure of AA   primarily revealed a few extra-large grains. In addition, the AA billets revealed equiaxed coarse grains coupled with a few fine grains that were displayed in some limited areas inside the extra-large grains. The minimum and maximum recorded grain size of the AA billets was 1.106 and 34.02 µm, respectively, with the mean grain-size being 6.338 µm. Furthermore, the grain boundaries (GB) map shown in Figure 3b revealed a limited number of LAGBs, which are displayed as red lines.
Processing through 1-pass using the ECAP die with an internal channel angle of 90° (Figure 4a) resulted in a bimodal structure in which heavily deformed and distorted grains were revealed coupled with newly formed fine grains, which indicated that the imposed strain resulted in the dynamic recrystallization process in some areas and formation of the new fine grains, whereas it was not sufficient to refine the grains in other areas. The produced grain size ranged from 0.638 to 25.45 µm, with an average grain size of 1.9587 µm, as listed in Table 1. Furthermore, from Figure 4a it was clear that 1-pass processing resulted in increasing the fraction of LAGBs. The grain size distribution is shown in Figure 6, whereas the misorientation angle distribution is shown in Figure 7 for the Mg billets before and after ECAP processing.
Processing through 2-passes using the 90°-die revealed that the microstructure was dominated by fine grains that were not present in the AA sample before. A few residual large grains remained from the AA sample, but they were heavily deformed. The coarse grains that remained were still equiaxed and homogenously structured. Processing through 2-passes of route A (2-A) revealed increase in areas of fine grains and reduction in areas of coarse grains, as shown in Figure 4c, which was attributed to the increase in the amount of plastic strain through increasing the number of passes. The grain size ranged between 0.564 and 22.62 µm, with an average grain size of 1.692 µm, which indicated that 2-A resulted in decreasing the grain size by 73.3% compared to the AA counterpart. In terms of LAGBs, Figures 4d and 7 revealed that 2 A led to a significant increase in the fraction of LAGBs. In addition, processing through 2-passes of route Bc (2-Bc) resulted in significant refinement (Figure 4e); the grain size ranged between 0.507 and 9.291 µm, and the average grain size was reduced by 76.45% compared to the AA condition. In contrast 2-Bc revealed a significant reduction in the LAGBs (as shown in Figure 4f), which indicated that LAGBs had transferred into HAGBs and an UFG recrystallized structure was attained. Processing through 2-passes of route C (2-C) resulted in significant increases in the areas of recrystallized fine grains, as shown in Figure 4g, and the grain size ranged between 0.677 and 11.052 µm, with average grain size of 1.574 µm, indicating that 2-C reduced the average grain size by 75.1% compared to the AA counterpart. Contrastingly, 2-C revealed a significant increase in the fraction of LAGBs, as shown in Figures 4h and  7. From the aforementioned findings, it was clear that route Bc is the most effective in obtaining UFG equiaxed grains, followed by route C, whereas route A resulted in more elongated grains compared to the others. Furthermore, it can be concluded that route Bc resulted in producing a higher fraction of fine grains, and hence, fine grains with smaller average grain size (as shown in Figure 6 and tabulated in Table 1), followed by route C and finally route A.
To study the effect of ECAP die angle on microstructural evolution, pure Mg billets were processed through 2-passess of different routes. ECAP processing through 1pass using the 120°-die revealed fewer areas with UFG structure compared to the Mg billets processed using the 90°-die, as shown in Figure 5a. This can be explained by the lower plastic strain of the 120°-die compared to the 90°-die, according to equation (1). Table 1 revealed that 1-pass using the 120°-die resulted in grain size ranging from 1.106 to 24.82 µm, with average grain size of 2.62 µm. In contrast, 1-pass using the 120°-die displayed a higher fraction of LAGBS compared to the 90°-die (Figure 7). Similar to the 90°-die findings, strain accumulation through 2-passes revealed increasing UFG areas and decreasing areas of coarse grains. Processing of 2-A resulted in a bimodal structure, wherein UFG coexisted with elongated coarse grains, as shown in Figure 5c. The grain size ranged between 0.677 and 24.795 µm, with an  average grain size of 1.754 µm, which indicated that 2-A resulted in refining the grain size to 72.3% compared to the AA counterpart. In addition, 2-A resulted in significant increases in LAGBs, as shown in Figure 5d. Contrastingly, 2-Bc and 2-C resulted in refining the average grain size of pure Mg to 70 and 69.4%, respectively, compared to the AA counterpart. In terms of LAGBs, both 2-Bc and 2-C revealed significant increases in the fraction of the LAGBs compared to the AA condition ( Figure 5f and h). Furthermore, from the aforementioned findings, it was clear that for the 120°-die, route A is more effective in grain refining compared to routes Bc and C. The heterogeneity associated with the AA-Mg microstructure before the ECAP process causes regions to respond differently to the resulting strain. The imposed strain caused dynamic recrystallization to occur in regions with HAGBs and subsequently caused their evolution into extremely fine grains. A rapid evolution of the microstructure occurred in routes Bc and C due to the elevated extent of recoverable shearing. However, this sort of evolution was hindered in samples processed by route A due to the repetitive nature of the route, which served only to distort the Y plane. For the 90°-die, route Bc revealed transference of a higher fraction of LAGBs into HAGBs (Figure 4f) compared to routes A and C. In contrast, for the 120°-die route A revealed transference of a higher fraction of LAGBs into HAGBs (Figure 5h) compared to routes Bc and C. Accordingly, the higher the transfer of LAGB fractions into HAGBs, the higher the refinement of the grain size and better the strengthening effect, resulting from more resistance to the dislocation motion.
Similar findings were reported in earlier studies. Lei and Zhang [50] reported that 4-passes were enough to refine the pure Mg grain size up to 1.75 µm. Xu et al. [55] reported that processing AZ31 through 4-passes resulted in achieving a homogenous equiaxed microstructure with an average grain size of 7 µm. Alateyah et al. [28] reported that 4 Bc using 90°ECAP die is the most effective ECAP processing condition for ZK30 alloy; 4-Bc, 4-A, and 4-C conditions resulted in refining Mg alloy from 26.69 to 1.94, 2.89, and 2.25 µm, respectively. In addition, Alateyah et al. [22] found that the ECAP die with 90°revealed more  efficiency in grain refining of pure Mg, and 4-Bc processing through the ECAP dies with 90°and 120°resulted in reducing the grain size of the AA billets from 6.34 to 0.88 µm and 1.89 µm, respectively. Sankuru et al. [56] reported that 4-passes of all route types led to achieving homogenous equiaxed grains of pure Mg, whereas 4-Bc was the most effective route in grain refinement. Gzyl et al. [57] reported that processing of AZ31B alloy through route A showed less tendency to fracture compared to route Bc and C. Tong et al. [58] reported that route Bc revealed more efficiency in grain refinement of Mg-Zn-Ca alloy, followed by route C and finally route A. In addition, they explained the reduction in LAGBs during the multiple passes by the transferring into HAGBs. From Figure 8a, the texture of the AA billets seems to possess strong texture components with a max intensity of 24.26 times random, with the densest collection of {0001} poles occurring on the same horizontal line as the extrusion direction (ED). During plastic deformation of HCP metals, the ideal shear texture is predominately dependent on the active slip systems. HCP crystals have fewer slip systems than the FCC and BCC crystal structures, being restricted to only the basal {0001} <11-20>, pyramidal {10-11} <11-20>, or prismatic {10-10} <11-20> slip systems [59,60]. After ECAP processing, the predominant texture was that of simple shear with the shear plane at a 45°angle with the ED, which indicates that the basal slip system became active with ECAP processing.

Crystallographic texture
Processing through 1-pass using the 90°-die resulted in rotating the {0001} basal planes by about 45°around the normal direction as shown in Figure 8b, which is aligned with the shear plane normal (SPN), which can be attributed to the basal slip activation during the first ECAP pass [22]. Furthermore, 1-pass resulted in reducing the max intensity of the texture from 24.26 times random for the AA billets to 9.77 times random, which can be attributed to the few numbers of active slip systems after 1-pass processing and agreed with ref. [55]. The crystallographic texture of the ECAP processed samples was found to be weaker across all die angles and routes used for 2-passes processing, which negatively affects the strength. Figure 8 shows the texture strength of the samples processes using the 90°-die. The weakest texture was recorded in the sample processed via route C, with a maximum texture intensity of 5.8 times random. The samples processed via routes A and Bc with the same die angle showed slightly stronger texture intensities of 9.59 and 10.35 times random, respectively.
The samples processed with die angle 120°showed slightly stronger texture components, as shown in Figure 9. Figure 9a shows that 1-pass processing using the 120°die led to a strong texture; the max recorded intensity was 23.22 times random. The {0001} basal planes were oriented parallel to the ED. Furthermore, 2-passes of the different routes resulted in a much weaker texture, as shown in Figure 9. The strongest texture component occurred in route C, which was 14.66 times random, whereas those of routes A and Bc were 7.19 and 11.66 times random, respectively. It can be argued that the shear plane positions change in the second pass, which results in the SPN alignment with the shear direction (SD) and TD with the ED. However, using route A resulted in strong basal poles that rotate around the TD axis by 130°, which agreed with that reported by Gautam and Biswas [61].
The texture components seem to have rotated significantly away from their ideal position. This can be attributed to the rotation of SD and SPN relative to the die angle as a consequence of the 120°-die angle. The intense {0001} poles were tilted with respect to the ED with various angles depending on the route used. As previously stated, all processed texture components were of lower intensity and strength, compared to the AA condition, which becomes evident by looking at the {0001} pole figures (Figures 8 and 9). This decline in intensity can be argued to represent the slip system activation. Indeed, the rotation of the basal plane during ECAP processing can be explained by the shearing stresses parallel to the basal planes [55]. In addition, the crystallographic texture findings of pure Mg perfectly matched with earlier studies for pure Mg [22,62], AZ31B Mg alloy [63], ZK30 alloy [27,28], and AZ31 alloy [64].

Mechanical properties
HV values were measured for the AA and ECAP processed samples through different ϕ (90°and 120°) and as a function of the three different routes (A, Bc, C). The HV values are illustrated in Table 2. The average HV value of the AA sample was 26. Inspection of Table 2 shows that hardness increased considerably after ECAP processing. Moreover, the 90°-die consistently produced higher hardness values than the corresponding ϕ = 120°-die across all routes. ECAP processing through 1-pass using the 90°-die and 120°-die resulted in increasing the HV value by 61.5 and 50%, respectively, compared to the AA counterpart. In addition, 2-A, 2-Bc, and 2-C processing through the 90°die displayed additional increases in the HV values of 76.9, 96, and 84.6%, respectively, compared to the AA counterpart. Furthermore, 2-A, 2-Bc, and 2-C processing through the 90°-die experienced an additional increase in the HV values by 9.5, 8.5, and 9%, respectively, in comparison with the samples processed through 2-A, 2-Bc, and 2-C using the 120°-die.
Accordingly, the HV findings were matched with the microstructural evolution shown in Figures 4 and 5. In addition, the significant improvement in the HV values evolved as a result of the underlying grain refinement, route Bc possessed the lowest grain size. Consequently, the decrease in hardness with increasing ϕ can be explained by the lower plastic strain imposed on the samples at higher angles.
Tensile tests were conducted on the AA and ECAPed Mg billets at room temperature. The stress-strain curves  Figure 10. From Figure 10, it is clear that neither the ECAP die angle nor the route type had a significant effect on the yield strength, and all the processing conditions displayed insignificant change in the yield strength. The ultimate tensile strength (σ u ) and the ductility Mg at fracture are listed in Table 2. Table 2 clearly shows that both σ u and Mg ductility significantly improved after processing. For the ECAP die with channel angle of 90°, 1-pass increased σ u by 31.7%, coupled with improving the ductility by 76%, whereas 1-pass using the 120°-die resulted in increasing the σ u by 19.6%, coupled with improving the ductility by 57%, compared to the AA counterpart. ECAP processing through the 90°-die led to improving σ u by 14.1, 38.4, and 43.75%, coupled with improving the Mg ductility by 80.9, 73.5, and 47.6%, through processing via 2-A, 2-Bc, and 2-C, respectively, compared to the AA counterpart. In comparison with the sample processed through 2-A, 2-Bc, and 2-C using ECAP die with 120°, their counterparts processed using the 90°-die revealed notable improvements in σ u by 6.1, 13.14, and 23.8%, respectively, whereas the ductility was reduced by 5.26, 1.35 and 18.4%, respectively. Accordingly, the 120°-die samples consistently had higher ductility values than those of the corresponding 90°-die across all routes, which is a result of the reduced strain applied. The increase in σ u with both 90°-and 120°-dies can be attributed to the ultrafine grains produced from processing. In addition, the 90°-die revealed higher σ u compared to the 120°-die counterpart due to the higher plastic strain of the 90°-die compared to the 120°-die, according to equation (1), which resulted in higher grain refinement, as shown in Figures 4 and 5 and as listed in Table 1. Similar findings were reported earlier for pure Mg [22,26] and ZK30 [24,27,28]. Furthermore, the reduction in the ductility in 90°billets during processing through multiple passes of different route types could be assigned to the smaller grain size compared to the 120°-die, as a result of material strengthening, leading to ductility reduction [22]. According to Hughes' theoretical model, the imposed strain results in dislocation movement [65]. The dislocations are then absorbed by the LAGBs, which consequently gradually transform into stable HAGBs. ECAP also results in the creation of new dislocations, subsequently increasing the dislocation density, which negatively affects the dislocations' ability to move [66]. Thus, the hardness and ultimate tensile strength of AA-Mg are enhanced after the ECAP process. Finally, grain refinement caused grain-boundary strengthening of the samples [67].

Conclusion
Pure Mg billets were processed through two ECAP dies with internal channel angle of 90°and 120°through up to 2-passes of routes A, Bc, and C at 225°C. Microstructural evolution, crystallographic texture, and mechanical properties of the Mg billets were investigated to study the effect of ECAP die angle and route type on the plastic strain homogeneity. The following conclusions can be drawn: 1. The 90°-die is more capable of grain refinement than the 120°-die. 2. Route Bc is the most effective in grain refinement compared to other routes. 3. Processing via 2-Bc using the 90°-die experienced a homogenous distribution of UFG with a reduced average grain size of 74.45% compared to the AA counterpart. 4. Processing of 2-C using the 120°-die displayed the strongest texture compared with the other processing conditions with a texture intensity of 14.66 times random. 5. Processing of 2-Bc using the 90°-die revealed an increase in the HV of 96% compared to the AA counterpart. 6. The 90°-die revealed higher tensile strength compared to the 120°-die. 7. Processing of 2-A, 2-Bc, and 2-C through the 90°-die led to improved tensile strength by 14.1, 38.4 and 43.75%, respectively, compared to the AA counterpart.
Acknowledgements: The researcher would like to thank the Deanship of Scientific Research, Qassim University, for funding the publication of this project.
Funding information: This research received no external funding.

Conflict of interest:
The authors declare no conflict of interest.
Institutional review board statement: Not applicable.
Informed consent statement: Not applicable.
Data availability statement: All raw data supporting the conclusions of this paper were provided by the author.