Effect of temperature on tensile behavior, fracture morphology and deformation mechanisms of Nickel-based single crystal CMSX-4

The effect of temperature on the tensile behavior and deformation mechanisms in a single crystal super alloys CMSX-4 is addressed and deduced by transmission electron microscopy in the temperature range from room temperature to 1100 degrees C. It is found that the tensile yield strength reaches a peak at 800 degrees C. And then, the yield strength decreases with increasing temperature. At room temperature, anti-phase boundary shearing dominates the plastic deformation. From 800 degrees C to 850 degrees C, the plastic deformation mechanism is mainly controlled by stacking fault shearing. The Kear-Wilsdorf locks have also appeared. When the temperature reaches at 950 degrees C, dislocation loops with anti-phase boundary shearing of the xfffc; precipitates are presented. Above 950 degrees C, the plastic deformation mechanism is processed by the rafted structure of the precipitates by-passing, i.e., Orowan by-passing and dislocation climb. Finally, according to the experimental results, the variety of stacking faults with temperatures and the relationship between the yield strength and plastic deformation mechanism are discussed. (c) 2022 Elsevier B.V. All rights reserved.