The Correlation Between Grain Orientation Evolution and Stress Rupture Properties of Waspaloy

Abstract

The grain orientation evolution of Waspaloy with different initial grain sizes under the same stress rupture tests were systematically investigated by electron back-scattered diffraction (EBSD). Correlation between the grain orientation evolution and the changes of stress rupture properties were also studied. The results show that the specimens with different initial grain sizes present different grain orientation evolution behaviors during the constant stress loading process, and the stress rupture lives of alloy are closely related to the orientation changes. Specimen with large initial grain size generally exhibits a small lattice rotation, in the [101] orientation and consequently, a long stress rupture life. On the converse, the fine grain specimen exhibits significantly shorter life with much more [111] orientation, since the lattice is obviously rotated and the deformation has little coordination. Further analysis shows that initial grain size affects the misorientation distribution in the grain, which has a significant influence on the stress rupture life. The lower the misorientation angle and the higher the proportion of the low-angle misorientation is, the longer the rupture time it exhibits.