Effect of long-term natural aging on the microstructural characteristics of an extruded WE54 alloy

Abstract

The microstructure and the corresponding crystallographic texture of the as-extruded WE54 alloy after natural aging for 11 years at room temperature have been characterized by the Electron backscatter diffraction (EBSD) technique. Before natural aging, the as-extruded WE54 exhibited equiaxed microstructure with a strong splitting basal texture and the presence of second particles along the extrusion direction (ED). Unexpectedly, long-term aging led to the formation of elongated deformed grains along ED having {11–20}<10-10> and {0001}<10-10> orientations with a partial development of fine static recrystallized grains by continuous and discontinuous mechanisms. It is believed that the origin of such grain structure development is the residual stored strain during the extrusion processing and the strain field induced from the solute Nd and Y atoms diffusion through the long-term natural aging. Artificial aging at 400 °C for 60 min demonstrated that the elongated deformed grains disappeared and left behind a heterogeneous recrystallized microstructure with a weak basal texture.