## 3 Results and Discussion
### Impact of ECAP Processing Factors
#### 3.2.3 Tensile Properties  
Tensile tests were conducted on Mg specimens in the form of billets prior to and following ECAP processing. The tensile findings, such as \(\sigma_{\rm u}\) and Mg percent elongation at fracture or ductility (D\({}_{\rm u}\)), are tabulated in Table 11 (Appendix A). Grain size was substantially minimized as ECAP passes were increased, as shown in Figures 3-5. As a result, given that the grain decrease in size is unrelated to the increase in \(\sigma_{\rm u}\), there are further variables impacting it. One of them is the crystallographic texture, which has an essential function in reinforcing Mg billets because of the substantial texture anisotropy (as illustrated in Figure 5) of Mg slip systems with hcp crystal structure. Moreover, Mg billet characteristics may be altered through the initiation of non-basal slip methods [48], where analogous results were published previously in [75]. The AA billets experienced \(\sigma_{\rm u}\) and D\({}_{\rm u}\) of 235 MPa and 0.23. From Table 11 it is revealed that 1P through the 90\({}^{\circ}\)-die experienced a substantial increase in \(\sigma_{\rm u}\) and D\({}_{\rm u}\), from 32% and 67%, respectively. Upping the strain to 2 Bc (using the 90\({}^{\circ}\)-die) only marginally increased the \(\sigma_{\rm u}\) by 7% while decreasing the D\({}_{\rm u}\) by 3% in comparison to the 1P. When contrasted with its AA equivalent, ECAP-processed via a 90\({}^{\circ}\)-die for two passes through route A, Bc, and C showed increases in \(\sigma_{\rm u}\) of 14.1%, 38.4%, and 43.75%, respectively, and increases in Mg ductility of 80.9%, 73.5%, and 47.6%, respectively. When the ECAP was raised to 4 Bc, it was found that the \(\sigma_{\rm u}\) increased by 10% and the D\({}_{\rm u}\) decreased by 20% relative to the 2 Bc equivalent. Alternatively, 1P at \(\phi=\) 120\({}^{\circ}\) displayed a notable boost in \(\sigma_{\rm u}\) of 17% and D\({}_{\rm u}\) of 47%. Taking ECAP passes all the way to 2 Bc showed that the \(\sigma_{\rm u}\) was augmented by 5%, while the D\({}_{\rm u}\) was augmented by 12%, both compared favorably to their 1P equivalents. While the D\({}_{\rm u}\) was lowered by 5.26%, 1.35%, and 18.4% in the 90\({}^{\circ}\)-die of the 2A, 2 Bc, and 2C samples, respectively, the 120\({}^{\circ}\)-die showed a 6.1%, 13.14%, and 23.8% enhancement in \(\sigma_{\rm u}\). As a consequence of the lowered strain implemented, the samples from the 120\({}^{\circ}\)-die steadily seemed to have significantly greater ductility than their 90\({}^{\circ}\)-die counterparts among all routes. Additional enhancements of 10% in \(\sigma_{\rm u}\) and 5% in D\({}_{\rm u}\) were discovered when employing 4 Bc. In both the 90\({}^{\circ}\) and 120\({}^{\circ}\)-dies, the increase in \(\sigma_{\rm u}\) is ascribable to the formation ultrafine grains that result from the processing step. The outcomes of tensile testing agreed with the refinement of the grain size as a function of number of ECAP passes (Figures 3-5). The buildup of strain is responsible for the rise in \(\sigma_{\rm u}\), which is in turn attributable to the noticeable rise in texture intensity as the number of ECAP passes increased. Additionally, the production of UFG materials was also clearly impacted by an increase in HAGBs in the ECAP process [28; 50]. [PERSON] theoretical model [76] provided an explanation, noting that strain caused dislocations to move. Dislocations were irreversibly consumed by LABs as strain increased; as a result, low-angle grain boundaries (LAGBs) were slowly changed into steady HAGBs, and the grains were refined as a consequence of the creation of HAGBs. Consequently, the increased strength might have been traced back to the finer grain size. However, the high dislocation density produced by ECAP processing reduced the dislocation mobility [77], which in turn raised the hardness outcomes and the tensile strength results of the processed ECAP Mg billets.