The effects of Ta on the tensile behavior and deformation mechanisms of a Ni-based single crystal superalloy were investigated in this study from room temperature to elevated temperature.The findings demonstrated that...The effects of Ta on the tensile behavior and deformation mechanisms of a Ni-based single crystal superalloy were investigated in this study from room temperature to elevated temperature.The findings demonstrated that the higher content of Ta could improve the tensile properties of the alloy at different temperatures.Due to the different deformation mechanisms at various temperatures,the influence of Ta on tensile deformation varied.At room temperature,the higher content of Ta enhanced the solid solution strengthening,which would enhance the tensile strength of 6.5Ta alloy.After standard heat treatment of 6.5Ta alloy,precipitation of the secondaryγʹphase would hinder the movement of dislocations.When the temperature was elevated to 760℃,the higher content of Ta not only promoted the interaction of stacking faults to form Lomer-Cottrell(L-C)locks that impeded dislocation motion,but also reduced the occurrence of dislocation pile-up groups,thus enhancing the yield strength.At 1120℃,due to the narrowerγchannels and higher APB energy inγʹphase of the alloy with higher Ta addition,the processes of bypassing and shearing of dislocations were hindered,respectively.Meanwhile,the denser and more regular dislocation networks were formed in 6.5Ta alloy;and thus,the tensile strength of 6.5Ta alloy was enhanced.This study systematically investigated the effect of Ta on the tensile behavior at three different temperatures,which provided an important theoretical basis for the design of nickel-based single crystal superalloys in the future.展开更多
基金supported by the National Key Research and Development Program of China under Grant No.2017YFA0700704the Middle-aged and Youth Talents in Scientific and Technological Innovation Project of Shenyang under Grant No.RC220440the Excellent Youth Foundation of Liaoning Province under Grant No.2021-YQ-02.
文摘The effects of Ta on the tensile behavior and deformation mechanisms of a Ni-based single crystal superalloy were investigated in this study from room temperature to elevated temperature.The findings demonstrated that the higher content of Ta could improve the tensile properties of the alloy at different temperatures.Due to the different deformation mechanisms at various temperatures,the influence of Ta on tensile deformation varied.At room temperature,the higher content of Ta enhanced the solid solution strengthening,which would enhance the tensile strength of 6.5Ta alloy.After standard heat treatment of 6.5Ta alloy,precipitation of the secondaryγʹphase would hinder the movement of dislocations.When the temperature was elevated to 760℃,the higher content of Ta not only promoted the interaction of stacking faults to form Lomer-Cottrell(L-C)locks that impeded dislocation motion,but also reduced the occurrence of dislocation pile-up groups,thus enhancing the yield strength.At 1120℃,due to the narrowerγchannels and higher APB energy inγʹphase of the alloy with higher Ta addition,the processes of bypassing and shearing of dislocations were hindered,respectively.Meanwhile,the denser and more regular dislocation networks were formed in 6.5Ta alloy;and thus,the tensile strength of 6.5Ta alloy was enhanced.This study systematically investigated the effect of Ta on the tensile behavior at three different temperatures,which provided an important theoretical basis for the design of nickel-based single crystal superalloys in the future.
