Automotive Temperature Deformation Behavior Of 5182 Aluminum Alloy And Its Pull-forming Properties Research

Lightweight materials in automotive applications have become a hot issue on the auto industry. 5182 aluminum alloy has become one of the automotive lightweight materials because of its excellent mechanical properties and forming properties. In this paper, the temperature deformation behavior and drawing performance of 5182 aluminum alloy were studied in order to provide the basis for the further development and optimization of 5182 aluminum body sheets.Through the simple temperature tensile test on the 5182 aluminum alloy in 50～300℃temperature, 0.001～0.1s^-1 strain rate stress range , temperature tensile deformation behaviors were explored. The true stress-strain curves were obtained. Using the improved Fields-Backofen equation and fitting the values of n, m and C, the constitutive equation of 5182 aluminum alloy was established on different deformation temperature and strain rates. Through the microscope, scanning electron microscopy and transmission electron microscopy, the Microstructure and fracture after deformation were observed and analyzed. Dynamic recovery and recrystallization in the process of temperature deformation were studied.Furthermore, through the warm drawing experiments, the paper has researched the warm forming performance and technology of 5182 aluminum alloy, and analyzed its fracture behavior of the drawing process. Under the technological condition of forming temperature 250℃, blank holder force 3.0N/mm², drawing speed 0.1mm/s and semi-solid lubricant, 5182 aluminum alloy can gain optimum drawing performance, and the drawing limit ratio (LDR) can reach 2.5. In the drawing process, the cracks in the flange fillet with straight edge have formed and expanded by the transitional region adjacent the straight wall, which eventually led sheet fracture.The strain hardening index value (n) is the best parameter to assess the drawing performances of the 5182 aluminum alloy sheet. In the same deformation temperature, greater the n value is, greater the drawing limit ratio (LDR) is. However, in different deformation temperature, the forming performance of 5182 aluminum alloy sheet depends mainly on the result of the interaction between plastic deformation ability and strain hardening capacity. With the increase in temperature deformation, n values decrease, but LDR values become bigger gradually and reach the maximum. Subsequently, n values continue to decrease, but LDR values begin to decline gradually.