INFLUENCE OF TEMPERATURE ON TENSILE BEHAVIORS OF K416B Ni-BASED SUPERALLOY WITH HIGH W CONTENT
Author(s): XIE Jun, YU Jinjiang, SUN Xiaofeng, JIN Tao, YANG Yanhong, Institute of Metal Research, Chinese Academy of Sciences
Pages: 943-950
Year: 2015 Issue: 8
Journal: Acta Metallurgica Sinica
Keyword: K416B Ni-based superalloy; tensile behavior; deformation feature; fracture mechanism;
Abstract: Ni-based superalloys with high content of W are often used to manufacture gas turbine vanes and high temperature forging dies due to high temperature capability and low cost. The microstructure of Ni-based superalloys consists of g matrix, γ′ phase and carbides generally. The deformation mechanisms of alloy mainly include dislocation loops formation, shearing of dislocation into γ′ phase and formation of anti-phase boundary(APB) and stacking fault. Although the deformation mechanism of Ni-based superalloys has been studied widely,the relationship between tensile property and deformation mechanism of K416 B superalloy at different temperature is still unclear up to now. Therefore, the influence of temperature on tensile behaviors of K416 B Ni-based superalloy with high W content was investigated in the present work by means of tensile test at different temperatures. It has been found that the yield and tensile strengths of K416 B alloy increase with rising temperature at 20~800 ℃. When the temperature exceeds 800 ℃, the tensile property of the alloy decreases gradually. The deformation feature of the alloy during tensile test at room temperature is that the dislocations shear into γ′ phase or cross γ′phase by Orowan mechanism. As the dislocations shear into γ′ phase, they decompose to form the stacking fault.The dislocation density in the matrix of the alloy increases with the rising temperature and the dislocation tangles in the matrix play the role of strengthening in the alloy during tensile test at 800 ℃. As the temperature furtherenhancing, the amount of dislocations shearing into γ′ phase increases and then the tensile strength of the alloy decreases. Under the condition of middle-low temperature, the brittle fracture occurs in the alloy due to the fact that the cracks are initiated and propagated along M6 C carbide with large size. During tensile test at high temperatures, the tensile fracture mode of the alloy is micro-porous aggregation along the g +γ′ eutectic interface, which is the main reason for the alloy exhibiting the ductile fracture.
Pages: 943-950
Year: 2015 Issue: 8
Journal: Acta Metallurgica Sinica
Keyword: K416B Ni-based superalloy; tensile behavior; deformation feature; fracture mechanism;
Abstract: Ni-based superalloys with high content of W are often used to manufacture gas turbine vanes and high temperature forging dies due to high temperature capability and low cost. The microstructure of Ni-based superalloys consists of g matrix, γ′ phase and carbides generally. The deformation mechanisms of alloy mainly include dislocation loops formation, shearing of dislocation into γ′ phase and formation of anti-phase boundary(APB) and stacking fault. Although the deformation mechanism of Ni-based superalloys has been studied widely,the relationship between tensile property and deformation mechanism of K416 B superalloy at different temperature is still unclear up to now. Therefore, the influence of temperature on tensile behaviors of K416 B Ni-based superalloy with high W content was investigated in the present work by means of tensile test at different temperatures. It has been found that the yield and tensile strengths of K416 B alloy increase with rising temperature at 20~800 ℃. When the temperature exceeds 800 ℃, the tensile property of the alloy decreases gradually. The deformation feature of the alloy during tensile test at room temperature is that the dislocations shear into γ′ phase or cross γ′phase by Orowan mechanism. As the dislocations shear into γ′ phase, they decompose to form the stacking fault.The dislocation density in the matrix of the alloy increases with the rising temperature and the dislocation tangles in the matrix play the role of strengthening in the alloy during tensile test at 800 ℃. As the temperature furtherenhancing, the amount of dislocations shearing into γ′ phase increases and then the tensile strength of the alloy decreases. Under the condition of middle-low temperature, the brittle fracture occurs in the alloy due to the fact that the cracks are initiated and propagated along M6 C carbide with large size. During tensile test at high temperatures, the tensile fracture mode of the alloy is micro-porous aggregation along the g +γ′ eutectic interface, which is the main reason for the alloy exhibiting the ductile fracture.
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