The Role of Residual Stress in Anisotropic Mechanical Properties of Titanium Alloy after Rolling

It is found that U-shaped titanium alloys are more likely to fracture perpendicular to the rolling direction in engineering applications. To explore the root cause of this mechanical anisotropy, we carried out tensile, fracture toughness and residual stress tests on U-shaped titanium alloys along and perpendicular to their rolling directions. In combination of x-ray diffraction tests, a full-field residual stress measurement technique combining digital image correlation and layer-removal method was also developed to evaluate residual stress distribution in different directions of the materials. The results show that the titanium alloy exhibits anisotropic mechanical properties after rolling. Its fracture strain and toughness are lower perpendicular to the rolling direction, but the strength limit is higher than along the rolling direction. The main reason is the difference in the distribution of residual stress in the vertical and along the rolling direction. This work may provide guidance for process optimization and structural design of titanium alloys.