Springback analysis of 6016 aluminum alloy sheet in hot V-shape stamping

Springback behavior of 6016 aluminum alloy in hot stamping was investigated by a series of experiments under different conditions using V-shape dies and a finite element model which was validated reliable was used to further elucidate the springback mechanism. The effects of initial blank temperature, blank-holding force, die closing pressure and die corner radius were studied. It is found that springback decreases remarkably as the initial blank temperature rises up to 500 °C. The springback also reduces with the increase of die holding pressure and the decrease of die corner radius. Under different initial temperatures, the influence of blank-holding force is distinct. In addition, the bending and straightening of the side wall during the stamping process is found to interpret the negative springback phenomenon.

Microstructure and texture evolution of 6016 aluminum alloy during hot compressing deformation

Microstructure and texture in 6016 aluminum alloy during hot compression were researched with a uni- axial compression experiment. Through the electron back- scattered diffraction （EBSD） and X-ray diffraction （XRD） analysis technology, it is shown that the subgrain nucle- ation and recrystallization occur in 6016 aluminum alloy during hot compressing, and strong rolling textures such as （110） fiber texture, Brass, S, and Goss form. With the deformation passes increasing, （110） fiber texture, Brass and S are enhanced. In the heat preservation stage after deformation, recrystallization continues until heat preser- vation for 60 s, and a duplex microstructure of deformation and recrystallization grains is built. At the beginning of heat preservation, recrystallization grains with the Goss texture and random orientation are formed in original grains with S or Brass texture, which makes the volume fraction of S and Brass texture decrease. Then, the complex grain growth process makes the volume fraction of Brass, S, and Goss texture increase, while that of random orien- tation decrease.

Superplasticity of 6016 aluminum alloy at elevated temperatures

The high-temperature plastic deformation be- haviors of 6016 aluminum alloy were investigated with the temperatures ranging from 420 to 540 ℃ and the strain rates ranging from 0.001 to 1.000 s-1. The results show that 6016 aluminum alloys possess superplasticity at 500 ℃ with the strain rates ranging from 0.001 to 0.010 s-1. The grain boundary sliding （GBS） is the main mechanism of superplastic deformation of 6016 aluminum alloy. In addition, a great number of O-type cavities, almost no V type, occur in the microstructure of superplastic deformed 6016 aluminum alloy. The dislocations gather near the grain boundaries to coordinate GBS deformation. The second-phase particles effectively prevent the growth of the recrystallized grains or plastic deformation grains and pin the moving dislocations during deformation.

Microstructures and properties of 6016 aluminum alloy with gradient composition

Weight reduction plays an important role in reducing fuel and emissions,and the heat-treatable 6016 aluminum alloy exhibits excellent application prospect in automobile lightweight.In this paper,ingot with constant Mg/Si ratio and decreased Mg and Si contents was obtained.Both the microstructure and the texture of 6016 aluminum alloy plate designed with different alloy compositions at the top/bottom were systematically investigated by electron backscatter diffraction technology(EBSD)measurement,as well as the room-temperature mechanical properties at the different positions with composition gradient.The results indicate that as Mg and Si contents increase,the grain size decreases,improving the cube texture with recrystallization and weakening the S texture.The strength of 6016 aluminum alloy decreases with lower Mg and Si contents.

Effect of position and force tool control in friction stir welding of dissimilar aluminum-steel lap joints for automotive applications

Widespread use of aluminum alloys for the fabrication of car body parts is conditional to the use of appropriate welding methods,especially if dissimilar welding must be performed with automotive steel grades.Friction stir welding(FSW)is considered to be a reasonable solution to obtain sound aluminum-steel joints.In this context,this work studies the effects of tool position and force control in dissimilar friction stir welding of AA6061 aluminum alloy on DC05 low carbon steel in lap joint configuration,also assessing proper welding parameter settings.Naked eye and scanning electron microscopy(SEM)have been used to detect macroscopic and microscopic defects in joints,as well as to determine the type of intermixture between aluminum and steel.The joint strength of sound joints has been assessed by shear tension test.Results point out that tool force control allows for obtaining joints with better quality and strength in a wider range of process parameters.A process window has been determined for tool force conditions to have joints with adequate strength for automotive purposes.