厚度和晶粒尺寸对高温合金带材起皱性能的影响

Wrinkling is one of the main defects that affect the quality and dimensional precision of part during plastic forming process of metal sheet. However, the influence of thickness and microstructure of sheet on wrinkling behavior is not clear. Taking ultra-thin GH4169 superalloy strip with different thicknesses (0.2~0.25 mm) and grain sizes (7.12~88.39 μm) as the research object, Yoshida buckling test was carried out. Then, the load-displacement curves of experimental and simulation results were compared so that the effectiveness of the numerical simulation was verified. By combining the theory of energy method with finite element numerical simulation, the wrinkling limit curves of GH4169 strip with different thicknesses and grain sizes were established. The results show that with the reduction of the number of grains in the strip thickness direction, the absolute value of the slope of the wrinkling limit curve of GH4169 strip decreases, which is more prone to wrinkle. With the decrease of the grain number in the thickness direction, the anisotropy among different grains is enhanced, and the deformation coordination ability of the material is weakened. As a consequence, the wrinkle resistance ability is weakened and the wrinkling of superalloy strip shows size dependence.