The effect of three-dimensional loading and texture on deformation mechanism of Zircaloy-4 alloy: Using space Schmid factor model

Abstract

The effect of three-dimensional loading and texture on deformation behavior (including basal <a>, prismatic <a>, pyramidal <a>, first and second order pyramidal <a+c> slips, tensile and compression twins) of Zircaloy-4 alloy sheet was systematically investigated using a new model:space Schmid factor model (SSFM). The SSFM was correlated with the results as calculated by EBSD technique. The results of compression tests and EBSD showed that yield strength was depended upon the orientation of the crystal and decreased in the sequence: TD > RD-35° > RD. Then, analysis of relationship between the loading direction and yielding anisotropy of the Zr-4 sheet revealed that the predominant deformation mode of the Zr-4 sheet was pyramidal <a+c> slip when compressed along the transverse direction (TD) and prismatic <a> slip when compressed either along the rolling direction (RD) or 35° away from the rolling direction (RD-35°). Besides this, a few {101‾2}<1‾011> tensile twins (TT) were exclusively observed in each case. However, the TT get activated easily in RD compression as compared to the other two directions. In general, the SSFM provided a well-substantiated explanation of the deformation mechanisms of the Zr-4 alloy sheet under different loading directions.