## 3 Results and Discussion  
### Tensile Stress  
The tensile properties of the specimens, such as the yield strength (\(\sigma\)\(t_{02}\)), UTS, and elongation at break, are presented in Table 2. The results of the tests indicated that the ME samples exhibited poorer mechanical properties than those of the samples made of monolithic AISI 316 L. Specifically, the average value of the yield strength (141.9 \(\pm\) 14.1 MPa) was lower by 17% compared to that of the monolithic material. The average value of UTS (426.6 \(\pm\) 23.7 MPa) was lower than that of the monolithic material by approximately 12%. These results could be attributed to the larger equiaxed grains and full austenitic structure after the sintering phase [16; 21]. Regarding the elongation at break, the percentage values were close to those of the monolithic AISI 316L. The inherent porosity of the sample generated by this AM technique [29], particularly the open one, could deteriorate the ductility of the ME specimens owing to local stress concentrations.  
Figure 2: U-bend sample.  
To provide a wider context of the tensile properties of stainless steel 316L samples realized with ME, a comparison among tensile values collected in different works is reported in Table 3. On average, the obtained yield and tensile strength resulted slightly lower than the other values presented; conversely, the ductility set the highest level compared to the values available in literature.  
The tensile curves, represented in Figure 2(a), show a similar trend, demonstrating the repeatability of the printing process. However, the difference in UTS and elongation at break among the samples suggests a significant presence of defects (voids and residual stress as a result of thermal processes). No significant necking phenomenon was observed during the tests.  
Figure 2(b) depicts the failure modes of the specimens. Three samples exhibited fractures inside the useful length, indicated by two blue lines near the edge of the samples. In contrast, samples 3 and 4 show fractures near the file radius, which is a critical stress intensity zone.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{1}{c}{**Source**} & \(\boldsymbol{\sigma_{\text{62}}}\) **(MPa)** & **UTS (MPa)** & **Elongation at Break (\%)** \\ \hline This work & \(141.9\pm 14.1\) & \(426.6\pm 23.7\) & \(36.4\pm 3.15\) \\ \hline [PERSON] et al. [37] & \(140.77\pm 6.97\) & \(311.81\pm 39.96\) & \(12.48\pm 2.81\) \\ \hline [PERSON] et al. [23] & \(167\) & \(465\) & \(31\) \\ \hline [PERSON] et al. [18] & \(194\pm 19\) & \(441\pm 27\) & \(29.5\pm 3.8\) \\ \hline [PERSON] et al. [38] & - & \(296\pm 78\) & \(32\pm 16\) \\ \hline [PERSON] et al. [20] & \(155\) & \(500\) & \(32\) \\ \hline AISI 316L [36] & \(170\) & \(485\) & \(60\) \\ \hline \hline \end{tabular}
\end{table}
Table 3: Comparison of tensile properties among 316L specimens fabricated by means of the ME technique.  
Figure 3: Tensile stress–strain curves (**a**); fracture positions of the samples (**b**).  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{1}{c}{**\(\boldsymbol{\sigma_{\text{62}}}\) (MPa)**} & **UTS (MPa)** & **Elongation at Break (\%)** \\ \hline Sample 1 & \(161.3\) & \(464.1\) & \(41\%\) \\ \hline Sample 2 & \(125.0\) & \(407.3\) & \(37\%\) \\ \hline Sample 3 & \(134.6\) & \(405.9\) & \(32\%\) \\ \hline Sample 4 & \(132.9\) & \(409.0\) & \(32\%\) \\ \hline Sample 5 & \(155.7\) & \(445.2\) &