Simulation and Experimental Study of Recrystallization Kinetics of Nickel Based Single Crystal Superalloys

Abstract

Hot compression tests on cylinders using nickel-based single crystal superalloy DD6 were conducted to introduce the stored energy for recrystallization. Annealing was carried out at different temperatures for different time to investigate the kinetics of recrystallization of DD6. The experimental results show that the recrystallization rate increases gradually with temperature. The stress, strain and stored energy distribution of single crystal superalloy were modeled based one macroscopic phenomenon-based elastic-plastic model, considering the orthotropic properties of SX superalloys. Recrystallization microstructure on the crosssection perpendicular to the cylinder axis was simulated using cellular automaton (CA) method. The model can predict experimental results.

Plastic Deformation and Recrystallization of a Ni-Based Single Crystal Superalloy

“…Nowadays, nickel-based single-crystal (SX) superalloys have been widely employed for turbine blades [1]. However, the blade's geometry is becoming increasingly complicated to manufacture, and great cares should be taken to prevent defects, such as stray grains [2], freckles [3], recrystallization (RX) [4][5][6][7] etc. RX can be ascribed to plastic deformation during manufacturing process [8,9], and can occur during solution treatment even after relatively small degrees of plastic strains.…”

“…When examining the (001) indent more carefully, slip lines arise along the direction <011> (Fig.3(a)). Fig.3(b)shows the simulation results of shear strains using one elasto-plastic model[6,7], which considers the orthotropic mechanical properties of SX superalloys. The shear strains along the direction <011> are high, which conforms to the experimental results.…”