Article
Materials Science, Multidisciplinary
Bing Sun, Tiebang Zhang, Lin Song, Lei Zhang
Summary: This study investigates the microstructural evolution and dynamic recrystallization mechanism of a nickel-based superalloy PM EP962NP during isothermal compression at 1150 degrees C under different strain rates and strains. The results show that continuous dynamic recrystallization occurs when the strain exceeds 0.36. A processing window with high microstructure stability, including the evolution of DRX, y grains, and y' precipitates, is determined to be hot compression at 1150 degrees C with a strain rate of 0.001 s-1 and strains ranging from 0.69 to 1.20. In addition, the y' precipitates exhibit inhomogeneous sizes due to the interaction between dissolution and precipitation, with micron-scale blocky primary y' and nano-scale spherical secondary y'. Moreover, the abundant microstructural information related to the strain rates and strains can provide a reference for obtaining gradient microstructures through thermo-mechanical processes.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Chemistry, Physical
Jiawei Wang, Huaming Wang, Kangjie Li, Mingyuan Chen, Meiling Zhang, Bo Zhang, Jingwei Yuan, Xu Cheng, Shuquan Zhang, Yudai Wang
Summary: This study presents a novel rotated laser irradiation approach to inhibit the formation of stray grains in nickel superalloys. A numerical model is developed to understand the mechanism behind stray grain formation at the bottom of the molten pool. The results show that the number of stray grains decreases with an increased angle between laser irradiation and gravity direction, and well-aligned epitaxial growth without any stray grains can be achieved with a specific angle.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
Abdullah Alhuzaim, Stano Imbrogno, Moataz M. Attallah
Summary: This study investigated the deposition of Inconel 718 alloy powder using the Direct Laser Deposition (DLD) process, revealing the significant influence of laser power and heat input on grain structure and segregation, allowing for the control of structures with different properties.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
Bingchao Xie, Heng Li, Yongquan Ning, Mingwang Fu
Summary: This paper investigates the nucleation mechanisms at the 2-, 3-, and 4-grain junctions of a nickel-based superalloy and explores the microstructure evolution during dynamic recrystallization (DRX). It is found that a passive grain boundary bulging mechanism operates at 2-grain junctions, while a two-step strain-induced bulging dominates the DRX nucleation at 3-grain junctions. The nucleation priority increases from 2-, 3- to 4-grain junctions and can be quantitatively analyzed using the Taylor factors of the component grains. Understanding the DRX associated with grain junctions is crucial for tailoring the microstructure of nickel-based superalloy forgings.
MATERIALS & DESIGN
(2023)
Article
Physics, Applied
E. Barraud, T. de Resseguier, J. Baillargeat, S. Hemery, J. Cormier
Summary: In this study, the dynamic behavior of a nickel-based superalloy under shock loading was investigated using laser-launched flyers. It was found that different microstructures and heat treatment conditions significantly influence the dynamic failure mechanisms.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Engineering, Manufacturing
Jiawei Wang, Huaming Wang, Hongwei Gao, Xu Cheng, Dong Liu, Meiling Zhang, Shuquan Zhang
Summary: This study investigates the elemental segregation behavior and microstructure transformation of an as-deposited IC10 superalloy at different deposition heights using a developed microsegregation model in the directed energy deposition process. Results show that the microstructure and elemental segregation behavior vary with deposition height. The partition coefficient plays a major role in microsegregation behavior under rapid solidification conditions.
ADDITIVE MANUFACTURING
(2022)
Article
Automation & Control Systems
Prveen Bidare, Aldi Mehmeti, Amaia Jimenez, Sheng Li, Chris Garman, Stefan Dimov, Khamis Essa
Summary: This paper analyzes the influence of process parameters on the porosity, crack formation and microstructure of additively manufactured CM247LC nickel-based alloy. It demonstrates the feasibility of using the direct laser deposition (DLD) process to manufacture crack-free and low-porosity CM247LC samples. The study also shows that good bonding between Inconel 718 substrate and deposited layers can be achieved by using specific laser power, scanning speed, and powder flow rates.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Rui Li, Bin Han, Kai Zhao, Zhandong Wang, Yan Shi, Kedong Bi, Guifang Sun
Summary: The hot corrosion behavior and mechanism of IN718 nickel-chromium alloy and 1 wt % TiC-reinforced IN718 were studied in a saturated mixed molten salt at 700 degrees C. The addition of TiC improved the hot corrosion resistance by refining the grains and forming a protective layer of Cr2O3. The hot corrosion product layer thickness was reduced by about 26% in Sample D2 as compared to Sample D1, leading to lower weight loss and corrosion rate.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Chemistry, Physical
Yukang An, Xiaolong Xu, Lei Liang, Yuhong Zhao, Hua Hou
Summary: The rapid solidification of Ni-Cu alloy was studied, revealing changes in grain refinement with increased undercooling, indicating the occurrence of recrystallization. The grain refinement at large undercooling is mainly caused by stress-induced recrystallization.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
Xiaolong Xu, Yongchao Hao, Ruifeng Dong, Hua Hou, Yuhong Zhao
Summary: Using the deep undercooling rapid solidification method, Cu based alloy was studied at different undercooling degrees. It was found that grain refinement occurred in both large and small undercooling ranges for the two alloys. EBSD analysis showed that the grain refinement structures differed in grain orientations for large and small undercooling. The refinement mechanisms were dendrite remelting and fragmentation for low undercooling alloy, and stress-induced recrystallization for high undercooling alloy. A sudden drop in grain size near critical undercooling was observed for the high undercooling alloy, providing direct evidence of grain refinement due to recrystallization in non-equilibrium solidification structure.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Anastasia Dmitrieva, Olga Klimova-Korsmik, Marina Gushchina, Rudolf Korsmik, Grigoriy Zadykyan, Stepan Tukov
Summary: Cracking of nickel superalloys with a high content of gamma'-phase remains an unresolved problem, including in technologies for repairing gas turbine engines blades. Laser cladding is a method of material deposition used to repair parts exposed to aggressive environment and surface wear. The study found a high tendency to form segregation of refractory elements and carbides in the intergranular areas of Alloy ZhS32, which has a high propensity for hot cracking when exposed to laser radiation. The features of the structure and phase composition of the material for different cladding parameters were studied, and the main contribution of technological parameters to the formation of cracks is shown.
Article
Materials Science, Multidisciplinary
Yukang An, Lei Liang, Xiaolong Xu, Yuhong Zhao, Hua Hou
Summary: The microstructural evolution and grain refinement mechanisms in rapid solidification of Ni-Cu alloys were investigated. Small undercooling led to grain refinement through dendrite superheating and remelting, while large undercooling resulted in recrystallization at high angle grain boundaries and twin boundaries. The substructure of alloys with large undercooling showed minimal dislocations and defects. Furthermore, a sharp decrease in microhardness in the alloy with large undercooling suggests that plastic strain accumulated during solidification is dissipated, providing energy for recrystallization.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Nanoscience & Nanotechnology
Lin Zhou, Suiyuan Chen, Mingzhi Ma, Jing Liang, Jialu Chen, Mei Wang
Summary: This study investigates the dynamic recrystallization behavior of non-contact ultrasonic-assisted direct laser deposited alloy steel. The results show that ultrasonic power has a significant influence on the grain size and tensile properties of the prepared alloy steel samples. The introduction of non-contact ultrasonic induces dislocation movement and triggers dynamic recrystallization. The optimized ultrasonic power achieves the best strength-plasticity matching relationship and improved strong-plastic product performance.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
J. C. Guo, P. Rong, L. Wang, W. J. Chen, S. X. Han, R. N. Yang, X. W. Lei, W. J. Yao, N. Wang
Summary: The substrate orientation significantly affects the formation of stray grains in laser remelted single crystal superalloys, with a greater impact on (011) and (111) planes compared to the (001) plane. The susceptibility to stray grain formation is weakest in the (011) plane and strongest in the (111) plane, attributed to the lower volume fraction of local stray grains on the (011) plane. A laser repair performed in the (011) plane along the [100] direction can most effectively depress stray grain formation, providing insights into avoiding stray grain formation in future laser repairs of single crystal components.
Article
Materials Science, Multidisciplinary
Yong Hu, Hui-Ying Zhang, Wen-Jiang Kang, Cheng Chu, Yong-Qi Hu, Hao Zhang, Dong Zhang
Summary: The high temperature oxidation behavior of selective laser melting processed IN738LC alloy was studied at different temperatures. The phase composition and oxide layer morphology of the oxidation products were characterized, and the oxidation mechanism was discussed. The results showed that the oxidation kinetics followed a parabolic law at 900 and 1000 degrees C, with oxidation products composed of Al2O3, Cr2O3, and TiO2. During the initial oxidation, Cr preferentially oxidized to produce Cr2O3, Ti atoms diffused to the surface through the Cr2O3 layer to form TiO2, and Al atoms diffused along grain boundaries to form a dense Al2O3 layer. The presence of holes in the oxide film at 1000 degrees C reduced adhesion and adversely affected the oxidation resistance.
JOURNAL OF MATERIALS SCIENCE
(2022)
