Influence of strain rate and grain orientation on deformation behavior in zirconium alloys: a combined in-situ/ex-situ study

This study combines ex-situ and in-situ mechanical loading experiments to investigate the plastic deformation behavior of Zr-4 alloy at room temperature under different strain rates and loading modes. The results show that the tensile and compressive yield strengths (YS) in rolling direction (RD) are lower than those in transverse direction (TD), but the ultimate tensile/compressive strengths (UTS/UCS) are higher than those in TD. The yield strength demonstrates minimal tension–compression asymmetry, whereas a marked disparity is observed between the UTS and UCS. Changes in strain rate have little effect on Schmidt factor for prismatic   <a>  slip and {10–12} tensile twinning, but prismatic  <a>  slip Schmidt factor is generally higher during RD tensile than TD tensile, and {10–12} tensile twin Schmidt factor is generally higher during RD compression than TD compression. The study observed different types of twin pairs, with twin transmission mainly following high Schmidt factor and high geometric compatibility factor (m′). No twin activation was observed during RD tensile. During TD tensile, twins are activated over a wide range of angles. For TD and RD compression, twins are activated within a narrow range of angles.