Mohamed Ibrahim Abd El Aal

The lack in previous works concerned with a full study of the deformation homogeneity, and how to reach a high level of deformation homogeneity in the different directions of equal-channel angular pressing (ECAP) processed Cu samples was the motivation of the current study. Therefore, reaching a high level of deformation homogeneity of the copper through optimizing the imposed strain according to the used ECAP die angles was investigated. ECAP was performed using three die angles 90 ^o , 110 ^o , and 130° up to 4 passes at room temperature. Microstructural characterization using optical and scanning electron microscopy revealed grain refinement across all die angles, with the 90° die producing the finest and most homogeneous fine-grained structure due to the highest-imposed shear strain. Grain size decreased from 31.3 µm in the annealed condition to 2.7, 4.8, and 7.2 µm after 4 passes using the angles 90°, 110°, and 130° respectively (pressing direction). Similarly, grain size decreased to 3.3, 5.8, and 7.4 µm after 4 passes using the 90, 110, and 130° dies, respectively (transverse direction). At the same time, refinement was comparatively less pronounced at higher die angles. Hardness mapping across ZY, YX, and ZX planes demonstrated significant strengthening and improved deformation homogeneity with increasing passes, with the 90° die consistently achieving the highest hardness values and lowest homogeneity index (H _index ). After 4 passes, hardness increased by 144.7, 115.1 and 95.6% (ZY plane), 129.3, 107.8 and 92.7% (YX plane), and 125, 104.3 and 91% (ZX plane) for 90°, 110°, and 130° dies, respectively. The mechanical properties of the 90° die deliver the highest strengthening (up to 403.7% in proof-strength and 70.3% in ultimate tensile strength), but with significant ductility loss. While the 110°and 130° dies show lower strengthening with relatively better ductility. Overall, the 90° angle provides the most effective processing route for producing fine-grained, high-strength Cu samples with excellent deformation homogeneity.

3D-FEM three-dimensional finite element simulations of equal-channel angular pressing (ECAP) and cyclic extrusion compression (CEC) of Al were performed to predict load-displacement behavior, strain distribution, and damage factor, and confirm them experimentally. The deformation mechanism in each process affects the load-displacement behavior. The load-displacement curves of the ECAP and CEC processes were predicted with a maximum deviation of 4.3% from the experimental loads. The complexity of CEC processing revealed a higher peak load by 265.4% than ECAP. The strain distribution indicates an increase from the bottom to the top and from the center to the surface after one pass and cycle of ECAP and CEC. However, the deformation homogeneity of both processes increases with further processing, resulting in higher homogeneity of ECAPed samples. The FEM average strain values after the ECAP and CEC were deviated by 2.3–9.6% from the theoretical equations. The microhardness distribution and homogeneity index effectively confirm the strain results. The average damage factor of the CECed samples was higher by 21.8–57.3% than that of the ECAP, confirmed through the heavily deformed shear bands observed after 10 cycles.

The influence of equal channel angular pressing (ECAP) and cyclic extrusion compression (CEC) of Al-1080 on the pressing load, microstructure, and tensile properties was investigated. The pressing peak loads of the CEC were 218.8–265.4% higher than those of the ECAP, with a more complex load behavior in the CEC process. The deformation morphology of the ECAP samples indicates an improvement in the deformation homogeneity with the number of passes. Shear band morphology with a decrease in the shear band width from the center to the outer surface makes up the predominant pattern of the CEC samples. The ECAP samples have 13.9–44% smaller average grain sizes, with 3.8–8.1% higher high-angle grain boundaries (HAGBs) than the CECed samples. The ECAP and CEC processing improve the tensile strength. However, the ECAP sample’s tensile strength (UTS) and the proof strength (σ_0.2) were 11.5–20.6 and 2.6–16.4% higher than that of CEC, without noticeable differences in elongation. The σ_0.2 values were predicted accurately with a deviation range of 1.8–7.3% from the experimental one. The ECAP samples are easy to process under lower loads. Moreover, ECAP samples have an equiaxed grain microstructure with a higher degree of deformation homogeneity and tensile strength.

This paper calculates the crashworthiness capability of glass‐reinforced epoxy composites over wrapped polyvinyl chloride (PVC) circular tubes with a triggering mechanism in the form of cutouts. The intended tubes were prepared by a wet wrapping method; after which they were subjected to quasi‐static axial compression. To compute crashworthiness indications, three design parameters, each at three levels, were used. The design parameters are the hole diameter (d), the hole's number (n), and the hole position (L). The Taguchi technique has been employed in the design of experiments (DOE) tactic to obtain the best crashworthiness parameters. With the maximum specific energy absorbed (SEA) and crashing force efficiency (CFE), the optimal parameters were found. Furthermore, the main effect, signal‐to‐noise ratio (S/N), as well as the analysis of variance (ANOVA), have been studied using the commercial software programme MINITAB 18. A few experiments were accompanied by the L9 orthogonal array. According to the results, “N” has the largest impact on the value of SEA with a contribution percent of 29.27%. While “d” has the main influence on the value of CFE with a contribution percent of 67.29%. Lastly, tests for confirmation were performed. to verify the predicted values in light of the experimental results. The optimized SEA developed tube is 74.72%, which is higher than the intact PVC tube and 12.29% lower than the intact hybrid tube. However, the optimum CFE was also 48 and 29.82% higher than the intact PVC tube and the intact hybrid tube, respectively.Highlights: The number of holes has the highest impact on SEA value by 29%. The ideal specimen enhances SEA by 75% compared to the intact PVC tube. Hole diameter has the most influence on CFE value by 67%. The best specimen improves the CFE by 48% related to the intact PVC tube.

This study explores the application of abrasive waterjet drilling (AWJD) for varied patterns of GF/Al mesh hybrid composites (neat glass NG, AG: Al in the exterior surface, and GA: Al in the center). Key parameters such as jet pressure (P), standoff distance (S), and traverse speed (V) are systematically varied, influencing material removal rate (MRR), hole taper ratio (), and roundness error (). Employing a Taguchi approach with an L9 design. It was indicated that the optimal conditions for maximum MRR are (P: 150 MPa, S: 2 mm, and V: 900 mm/min). V and S are the main influential parameters on and . Gray relational analysis (GRA) is employed for simultaneous optimization, enhancing drilling performance. The optimal parameters P of 150 MPa, S of 2 mm, and V of 300 mm/min are determined. Validation trials confirm the effectiveness of the determined parameters. A robust multiple regression equation is formulated, providing a predictive model that aligns closely with experimental observations.Highlights: The hybrid composites were drilled via a nontraditional process. The attributes of the hole geometry and the material removal impacts were studied. Operation parameters were optimized to improve MRR, , and . A multiple regression model and a confirmation test were performed and validated.