Temperature effects on tensile behaviors and relevant deformation mechanisms of a low-cost nickel-based single crystal superalloy containing 1.5% Re

In this work, tensile properties and relevant deformation mechanisms were investigated particularly in a novel low-cost second-generation nickel-based single crystal superalloy containing 1.5 wt% Re. The results showed that the experimental alloy exhibited an anomalous yielding phenomenon. The yield strength of alloy reached a peak value of 1120 MPa but the corresponding elongation was only 8.2% at 760 degrees C. Furthermore, the double yield phenomenon occurred at 900 degrees C and above whereas the strain softening behavior appeared at high temperatures. With increasing temperature, the main fracture mode gradually evolved from pure shear to microvoid accumulation fracture. The dislocations sheared into gamma ' particles and led to the formation of stacking faults, which was the dominant deformation mechanism below 760 degrees C. Particularly, the formation of both K-W locks and L-C locks is closely related to the peak yield strength of the alloy at 760 degrees C. At 900 degrees C, the tensile deformation was controlled by the combination of APBs shearing and Orowan bypassing gamma ' particles. As the temperature further increased to 1000 degrees C and 1100 degrees C, the dislocation networks formed on gamma/gamma ' interface could hinder the dislocations shearing into gamma ' particles. Meanwhile, Orowan bypassing and dislocations climbing became the dominant deformation mechanisms. The results of this work could provide vital support for development and application of low-cost SX superalloys.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

This work investigates the tensile properties and deformation mechanisms of a novel low-cost nickel-based single crystal superalloy containing 1.5 wt% Re. The alloy exhibits anomalous yielding behavior and undergoes double yield and strain softening at high temperatures. The main fracture mode transitions from pure shear to microvoid accumulation fracture with increasing temperature.