Deformation behavior in the uniaxial tension process of aluminum and aluminum alloy sheets under fluid pressure

To discover the deformation behavior and corresponding mechanism of the typical material under fluid pressure, we proposed a test method for the uniaxial tensile deformation performance of the sheet under fluid pressure and developed a testing device as well as a special fixture. The aluminum and aluminum alloy were tested based on this method, respectively. The results indicate that under the uniaxial tension, the plastic zone expands significantly and the uniform elongation decreases gradually with the increase of fluid pressure. The uniaxial tensile deformation performances of the sheets are improved differently corresponding to the various fluid pressures, and the increment of the elongation after fracture is higher for aluminum than aluminum alloy. The dimples on the fracture surface of the aluminum and aluminum alloy sheets are directionally distributed under fluid pressure. Aluminum sheets have no significant shear lip and the dimples become relatively evenly rounded. It is shown from our experiment that the deformation performance of the sheet can be significantly improved by applying fluid pressure, which provides a new way to improve the deformation ability of the sheets with low plasticity and expand their applications.