Tensile Properties and Deformation Behavior of Several Cast Ni-Based Superalloys Fabricated by Different Solidification Ways
来源期刊：Acta Metallurgica Sinica2017年第3期
论文作者：Hai-Tao Li Yong-Chun Liang Wan-Li Zhong Xue-Zhi Qin Jian-Ting Guo Lan-Zhang Zhou Wei-Li Ren
文章页码：280 - 288
摘 要：The tensile properties and deformation behavior of several cast Ni-based superalloys,respectively,in the equiaxed,columnar-crystal and single-crystal styles are comparatively studied.The effects of solidification way,heat treatment and strain rate on the tensile properties are discussed in detail.It is found that the reduction of grain boundaries by the feasible solidification ways offers cast Ni-based superalloys the potential capability of improving the mechanical properties,the ultimate achievement of which is also confirmed to lie on the appropriate modifications of chemical composition and heat treatment.The prolongation of solid solution facilitates the precipitation of fine secondary γ′ phase,whereas the extension of high-temperature aging leads to the coarsening of secondary γ′ phase.The combination of these two aspects has a crucial influence on the tensile properties.Under tensile applied stress,the surface grains of DZ-A alloy deform slightly,while the inner grains deform heavily.This deformation inhomogeneity is ascribed to the occurrence of cracks or oblique grains near the surface of specimens and the sliding or decohesion of grain boundaries between the surface and inner grains.Regardless of strain rate,the ILTDM（intermediate-low-temperature ductility minimum） phenomenon always happens in the temperature range from 400 to 600 ℃ in all the investigated alloys,the occurrence of which is closely related to the strong strain-hardening behavior in the deformation process.Finally,the interaction of slip bands which are the main deformation mode below 600 ℃ is established to be the essential reason for the strain hardening.
Hai-Tao Li1,2，Yong-Chun Liang3，Wan-Li Zhong3，Xue-Zhi Qin4，Jian-Ting Guo4，Lan-Zhang Zhou4，Wei-Li Ren5
1. South China University of Technology2. Guangdong Power Grid Co.Ltd3. Electric Power Research Institute of Guangdong Power Grid Corporation4. Institute of Metal Research,Chinese Academy of Sciences5. Shanghai University
摘 要：The tensile properties and deformation behavior of several cast Ni-based superalloys,respectively,in the equiaxed,columnar-crystal and single-crystal styles are comparatively studied.The effects of solidification way,heat treatment and strain rate on the tensile properties are discussed in detail.It is found that the reduction of grain boundaries by the feasible solidification ways offers cast Ni-based superalloys the potential capability of improving the mechanical properties,the ultimate achievement of which is also confirmed to lie on the appropriate modifications of chemical composition and heat treatment.The prolongation of solid solution facilitates the precipitation of fine secondary γ′ phase,whereas the extension of high-temperature aging leads to the coarsening of secondary γ′ phase.The combination of these two aspects has a crucial influence on the tensile properties.Under tensile applied stress,the surface grains of DZ-A alloy deform slightly,while the inner grains deform heavily.This deformation inhomogeneity is ascribed to the occurrence of cracks or oblique grains near the surface of specimens and the sliding or decohesion of grain boundaries between the surface and inner grains.Regardless of strain rate,the ILTDM（intermediate-low-temperature ductility minimum） phenomenon always happens in the temperature range from 400 to 600 ℃ in all the investigated alloys,the occurrence of which is closely related to the strong strain-hardening behavior in the deformation process.Finally,the interaction of slip bands which are the main deformation mode below 600 ℃ is established to be the essential reason for the strain hardening.
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