# Springback Behavior of AA 7075-T6 Alloy in V-Shaped Bending
## 3 Results and Discussions
### Effect of Temperature  
Aluminum alloys are significantly affected by high temperatures. The mechanical properties of aluminum at elevated temperatures are reduced considerably. Temperature effects are significant for machine parts operating at high temperatures and deformation operations. In this section, the results of V-shaped bending analyses performed at room temperature, 100 \({}^{\circ}\)C, 200 \({}^{\circ}\)C, 300 \({}^{\circ}\)C, and 400 \({}^{\circ}\)C, will be presented. Von Mises stress distribution of sheet metal at RT, 100 \({}^{\circ}\)C, 200 \({}^{\circ}\)C, 300 \({}^{\circ}\)C, and 400 \({}^{\circ}\)C is given in Figure 7 obtained from FE analyses. It was observed that the maximum von Mises stress in the sheet metal decreased as the temperature increased (Figure 7). While a focus of 783.44 MPa occurred at room temperature, the stress decreased to 53.05 MPa at 400 \({}^{\circ}\)C. Maximum von Mises stress occurred at the middle section of V-shaped bending specimens. It is observed that the stress values decreased significantly after springback [17; 37]. While 783.44 MPa stress occurred before springback at room temperature, this value decreased to 31.43 MPa after springback. At 400 \({}^{\circ}\)C, the values before and after springback were 53.05 MPa and 2.59 MPa, respectively.  
\begin{table}
\begin{tabular}{c c} \hline
**Bending Parameters** & **Levels** \\ \hline Thickness, t (mm) & 1–2–3 \\ \hline Bending angle, BA, (\({}^{\circ}\)) & 60–90–120 \\ \hline Bending radius, BR, (mm) & 4–8–12 \\ \hline Temperature, T, (\({}^{\circ}\)C) & RT–100–200–300–400 \\ \hline \end{tabular}
\end{table}
Table 3: Simulation parameters and levels.  
Figure 7: Von Mises stress distribution of sheet metal before and after springback (t = 1 mm) at (**a**) RT, (**b**) 100 \({}^{\circ}\)C, (**c**) 200 \({}^{\circ}\)C, (**d**) 300 \({}^{\circ}\)C, (**e**) 400 \({}^{\circ}\)C.  
The results obtained from the finite element analysis are presented in Table 4. As illustrated in Table 3, the springback angle was measured as 9\({}^{\circ}\) at room temperature and gradually decreased to 0.5\({}^{\circ}\) at 400 \({}^{\circ}\)C. This reduction highlights the significant influence of temperature on springback behavior. The forming characteristics of aluminum alloys at elevated temperatures have been extensively explored in the literature. Numerous studies report that when aluminum alloys are formed within the temperature range of 200-350 \({}^{\circ}\)C, formability parameters--such as drawability and elongation--can improve by approximately 200-300% [15; 38; 39]. While the springback value is higher at room temperature, the springback value decreases at higher temperatures [15]. Temperature appears to have an inverse effect on springback [9; 40; 41]. As the temperature increased, the bending load decreased, resulting in easier shaping. While 2318 N was required at room temperature, the bending load was reduced by 87% to 298 N at 400 \({}^{\circ}\)C. Figure 8 shows the variation in springback depending on the temperature.  
\begin{table}
\begin{tabular}{c c c c c c} \hline
**Temperature, T,** (\({}^{\circ}\)C) & **Bending Angle, BA (\({}^{\circ}\)C)** & **Bending Radius, BR (\({}^{\circ}\)mm)** & **Thickness, t (mm)** & **Max. Load (\({}^{\circ}\)C)** \\ \hline
22 & 90 & 4 & 1 & 2318 & 9 \\ \hline
100 & 90 & 4 & 1 & 2044 & 7 \\ \hline
200 & 90 & 4 & 1 & 1948 & 5 \\ \hline
300 & 90 & 4 & 1 &  
As shown in Figure 8, springback decreases as temperature increases. It has been observed that the temperature dramatically influences the high-temperature deformation [41; 42]. Researchers have shown that forming aluminum alloy sheets at high temperatures can increase formability and reduce springback [43; 44; 45].