Liu Zhiling,Meng Xinyu,Lyu Shaomin,et al.Study on Microstructure of GH4151 Nickel-based Superalloy Bar[J].Special Steel,2025,46(05):80-86. DOI: 10.20057/j.1003-8620.2025-00063.
Study on Microstructure of GH4151 Nickel-based Superalloy Bar
The high alloying degree of GH4151 nickel-based superalloy leads to cracks and crystal mixing defects in the billet process, which significantly reduces the material utilization rate. Meanwhile, the grain size of GH4151 is more sensitive to the temperature and time of solid solution treatment. Using vacuum induction smelting (VIM) + electric slag remelting (ESR) + vacuum arc remelting (VAR) triple smelting GH4151 ingot, after homogenization billet preparation into
200 mm round bar, through the metallurgical microscope (OM), scanning electron microscope (SEM) and back scattering electron diffraction (EBSD) characterization, system analyzed the bar typical microscopic tissue characteristics, heart crack and edge mixing defect formation mechanism, and combining the experiment, optimize the solid heat treatment process. The results demonstrate that, after standard heat treatment, the GH4151 bar exhibits a uniform equiaxed fine-grained structure, with an average grain size of 14.7 μm. A high density of secondary γ' precipitates (100 nm-200 nm) is uniformly distributed within the grains, significantly enhancing the high-temperature performance. The formation of central cracks is attributed to coarse grains and Laves phase precipitates induced by adiabatic temperature rise, with crack propagation predominantly guided by primary γ' precipitates and MC carbides. The edge abnormal grain structures are primarily caused by insufficient deformation, leading to incomplete recrystallization. Solution treatment experiments indicate that the optimal sub-solvus treatment condition is 1 120°C-1 150 °C for 90 min-240 min, effectively suppressing abnormal grain growth.
Chen Y , Lv S M , Xie X F , et al . Solidification behaviour and hot cracking susceptibility of a novel Ni-based superalloy [J]. Journal of Iron and Steel Research International , 2024 , 31 ( 4 ): 956 - 966 .
Gai Y C , Zhang R , Yang J X , et al . Effects of heat treatment on γ’ precipitates and tensile properties of a Ni-base superalloy [J]. Materials Science and Engineering: A , 2022 , 842 : 143079 .
Qiao S C , Liu S , Li N , et al . Abnormal grain growth in the Ni-based wrought superalloy GH4698 bar during heat treatment [J]. Journal of Materials Research and Technology , 2024 , 30 : 6563 - 6575 .
Li P K , Chen L , Bu H Y , et al . Effect of cooling rate on the Morphological changes in the secondary γ 'precipitation in FGH97 nickel-based PM superalloy [J]. Intermetallics , 2024 , 171 : 108344 .
Zhu L H , Pan H , Cheng J Y , et al . Dendrite evolution and quantitative characterization of γ’ precipitates in a powder metallurgy Ni-based superalloy by different cooling rates [J]. Journal of Alloys and Compounds , 2022 , 918 : 165677 .
Pan X Y , Jia C L , Qiu C L . On the stress rupture behavior and deformation mechanism of an advanced hot-extruded nickel-based superalloy [J]. Journal of Alloys and Compounds , 2022 , 926 : 166804 .
Liu P , Zhang R , Yuan Y , et al . Microstructural evolution of a Ni-Co based superalloy during hot compression at γ’ sub-/ super-solvus temperatures [J]. Journal of Materials Science & Technology , 2021 , 77 : 66 - 81 .
Zhang B Y , Wang Z T , Yu H , et al . Microstructural origin and control mechanism of the mixed grain structure in Ni-based superalloys [J]. Journal of Alloys and Compounds , 2022 , 900 : 163515 .
Zhang X G , Han H R , Zhou Y , et al . Effect of solution treatment on the microstructure and elevated temperature tensile properties of forged rene 41 superalloy [J]. Materials , 2024 , 17 ( 24 ): 6150 - 6159 .