The finite element method was applied to study the mechanics of rafting ofγ' precipitates in a single crystal Ni-based superalloy with the [001] orientation. The results show that the creep and rafting are closel...The finite element method was applied to study the mechanics of rafting ofγ' precipitates in a single crystal Ni-based superalloy with the [001] orientation. The results show that the creep and rafting are closely related with the stress and strain energy density distributions in the matrix channels. The application of an external stress leads to differential levels of von Mises stress and strain energy density, and the largest value of the stress appears at the corners of the matrix near the interface. Creep dislocations penetrate preferentially into the most highly stressed matrix channels where theγ'-phase rafting is also enlarged. Meanwhile, the von Mises stress ofγmatrix andγ' precipitate increases with the increase of temperature, thus the rafting becomes easier at a higher temperature. Moreover, according to the analysis of slip systems for the Ni-based superalloy, the critical external load for bowing a dislocation through a matrix channel at 950℃is about 180 MPa, which is consistent with the related experimental results.展开更多
基金Projects(10572019, 10672016)supported by the National Natural Science Foundation of Chinaproject(2005SM0035) supported by the Science Foundation of Beijing Jiaotong University, China
文摘The finite element method was applied to study the mechanics of rafting ofγ' precipitates in a single crystal Ni-based superalloy with the [001] orientation. The results show that the creep and rafting are closely related with the stress and strain energy density distributions in the matrix channels. The application of an external stress leads to differential levels of von Mises stress and strain energy density, and the largest value of the stress appears at the corners of the matrix near the interface. Creep dislocations penetrate preferentially into the most highly stressed matrix channels where theγ'-phase rafting is also enlarged. Meanwhile, the von Mises stress ofγmatrix andγ' precipitate increases with the increase of temperature, thus the rafting becomes easier at a higher temperature. Moreover, according to the analysis of slip systems for the Ni-based superalloy, the critical external load for bowing a dislocation through a matrix channel at 950℃is about 180 MPa, which is consistent with the related experimental results.
