Evolution mechanism of recrystallization in a nickel-based single crystal superalloy under various cooling rates during heat treatment

Abstract

Nickel-based single crystal (SX) superalloy is widely used in aero-engine turbine blades due to its excellent high-temperature performance and comprehensive performance [1] . It is well known that residual stresses generated during the removal of shell and cores can easily cause the formation of recrystallization layer on the surface of SX superalloy during heat treatment [2][3][4][5][6] . Due to the introduction of new grain boundaries (GBs) caused by the formation of recrystallization, the mechanical properties of SX superalloy are significantly decreased [7][8][9][10][11][12] . Jo et al. [7] reported that the early initiation of surface cracks in recrystallized specimens at 982 °C and 240 MPa could reduce creep life. Meng et al. [13]

An In Situ Resistance-Based Method for Tracking the Temporal Evolution of Recovery and Recrystallization in Ni-Base Single-Crystal Superalloy at Super-Solvus Temperatures

“…The second approach is directed at modeling the evolution of plastic strain and stress during casting with an aim to establishing thresholds for recrystallization. [13][14][15][16] Specifically, this was conducted using electrothermal mechanical testing (ETMT) capable of measuring a wide range of mechanical and physical properties. [17][18][19][20] It was proposed that not only was the history dependence of the strain path crucial, but it also pointed to the existence of a critical temperature range to delineate the work hardening portion of the plastic strain from the creep strain; the former being associated with an increasing dislocation density leading to recrystallization.…”