Texture Analysis for Determining the Rate Controlling Process in the Transient and Steady State Regions of Superplastic Flow

Abstract

Even anisotropic superplastic flow, which is a result of an elongated grain shape and texture, can lead to extreme elongations to fracture (superplasticity). Therefore, to identify the mechanisms of deformation present during superplastic flow alone, the effects of the microstructure should be eliminated first. Using an Al 5083 alloy, in which an equi-axed microstructure is present from the beginning, it is shown that grain boundary sliding, accompanied by grain rotations, is the rate controlling mechanism.

Common Mechanism for Superplastic Deformation in Different Classes of Materials

“…But, as noted by Bowen [30], only when GBS is rate controlling, the unbalanced shear stresses at the grain boundaries can lead to grain rotation and when the starting microstructure is anisotropic, it is essential to separate the microstructural effect from the texture effect for unequivocal inference. When this is done, both the systems studied by Bate et al are consistent with other texture results [10,31]. From Eq.…”