Abstract:In order to study the effect of shear deformation on microstructure, the formed shear hydro-bent tube of aluminum alloy was investigated by using electron back scattered diffraction (EBSD). The effect of internal pressure on the microstructures of the outside and inside corner zones was analyzed. The results show that the grain size is 50−100 µm at outside and 30−50 µm at inside under the internal pressure of 15.2 MPa, while the grain size of the undeformed tube is 100 µm. When the internal pressure reaches to 38.0 MPa, the grain is further refined and the grain size becomes 30−50 μm at outside and 10−20 μm at inside. The shear deformation plays an important role in the microstructure of two corner zones. The grain in the corner zones is refined and the size is becoming smaller with the internal pressure increasing. The grain size of inside is smaller than that of outside even if the internal pressure is the same for the different deformation degree.

Key words: hydroforming; microstructure; EBSD; tube; aluminum alloys