Dependence on temperature of compression behavior and deformation mechanisms of nickel-based single crystal CMSX-4

Abstract

The compression behavior under a temperature range from room temperature to 1100 °C were conducted on the single crystal superalloys CMSX-4. The objective of this study is to identify the effect of the temperature on the compression behavior and understand the deformation mechanism by transmission electron microscopy after yielding. Experimental results show that with increasing temperature, the yield strength increases until 850 °C. After that, there is a opposite trend in yield strength.At room temperature, plastic deformation is dominated by anti-phase boundary shearing. From 700 °C to 850 °C, the major anti-phase boundary and minor stacking fault shearing is observed. Besides, Kear–Wilsdorf locks are frequently observed especially at 800 °C and 850 °C, resulting in the best yield strength at these temperatures. At 950 °C, the deformation mechanism is mainly controlled by stacking fault shearing. With temperature increasing to 1100 °C, the dislocation network and rafted structure are formed, where the deformation mechanism is Orowan by-passing and dislocation climb. Finally, the formation of stacking faults with temperatures and the relationship between yield strength and deformation mechanism under compression tests are deduced.