Mechanism of precipitation distribution in WE43 alloy

The micromechanics of precipitation distribution in WE43 alloy was studied in detail using the electron back-scattered diffraction (EBSD) and Nye tensor method. It was observed that the dislocation density increases during deformation and aging leading to a decrease in the dislocation density of the sample. Further, it was found that low dislocation density is required for grains of near prismatic orientation (50° – 90°) compared to grains of near basal orientation (20° – 40°) to form the precipitates in grains under identical aging conditions. The orientation distribution functions (ODFs) showed that shifting of texture components along φ1 axis is more for near prismatic orientated grains compared to near basal orientated grains suggesting higher activity of screw dislocations in the former one. The higher activity of screw dislocations for near prismatic orientated grains is reflected in the formation of more dislocation debris of type on the (101¯0) planes. The dislocation debris of type is reflected in the higher values of α31 and α32 components in the Nye dislocation tensor matrix compared to near basal-orientated grains. The high density of dislocation debris accelerates the pipe diffusion resulting in the formation of more precipitates in the prismatic oriented grains compared to near basal oriented grains and the said precipitates are present mostly near the grain boundaries. The number of precipitates is more in the prismatic-oriented grains compared to near basal grains.