Static recrystallization behavior of AEREX350 superalloy

The recrystallization behavior of a commercial nickel–cobalt base superalloy, AEREX 350, is investigated by means of hardness test, X-ray diffraction, and microscopy. It is found that the alloy resists recrystallization up to a high temperature of 1025 °C. Recrystallized grains are readily formed at grain boundaries below this temperature; however, the growth of these new grains is inhibited by Widmanstätten η particles having coherent facets with the nickel matrix (γ). The passage of the recrystallization front results in coherency loss and consequently dissolution of the η platelets. Recrystallization proceeds with a discontinuous precipitation of the η phase behind the moving boundary.

Research highlights▶ The static recrystallization behavior of a complex superalloy, AEREX 350, is investigated. ▶ It is found that this alloy resists recrystallization to very high temperatures (1025 ̊C, 0.81Tm). ▶ TEM investigation showed evidence of grain boundary pinning by the Widmanstätten η platelets. ▶ Recrystallization of the AEREX 350 superalloy proceeds by the discontinuous precipitation of the η particles behind the moving boundary.