DDRX and CDRX of an as-cast nickel-based superalloy during hot compression at γ′ sub-/super-solvus temperatures

Xie, Bingchao; Yu, Hao; Sheng, Tao; Xiong, Yuhang; Ning, Yongquan; Fu, Ming

doi:10.1016/j.jallcom.2019.06.202

Cited by 88 publications

(13 citation statements)

References 64 publications

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“…It is widely acknowledged that the CDRX nucleation mechanism is related with the evolution of sub-grains, which can be estimated by misorientation analysis [ 32 , 33 , 34 ]. Figure 5 depicted that the point to point misorientations and the point to origin misorientations corresponding to the lines indicated in Figure 4 .…”

Section: Resultsmentioning

confidence: 99%

Investigation on Sub-Solvus Recrystallization Mechanisms in an Advanced γ-γ’ Nickel-Based Superalloy GH4151

Chen

et al. 2020

Materials

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Sub-solvus dynamic recrystallization (DRX) mechanisms in an advanced γ-γ’ nickel-based superalloy GH4151 were investigated by isothermal compression experiments at 1040 °C with a strain rate of 0.1 s−1 and various true strain of 0.1, 0.3, 0.5, and 0.7, respectively. This has not been reported in literature before. The electron backscatter diffraction (EBSD) and transmission electron microscope (TEM) technology were used for the observation of microstructure evolution and the confirmation of DRX mechanisms. The results indicate that a new dynamic recrystallization mechanism occurs during hot deformation of the hot-extruded GH4151 alloy. The nucleation mechanism can be described as such a feature, that is a primary γ’ (Ni3(Al, Ti, Nb)) precipitate embedded in a recrystallized grain existed the same crystallographic orientation, which is defined as heteroepitaxial dynamic recrystallization (HDRX). Meanwhile, the conventional DRX mechanisms, such as the discontinuous dynamic recrystallization (DDRX) characterized by bulging grain boundary and continuous dynamic recrystallization (CDRX) operated through progressive sub-grain merging and rotation, also take place during the hot deformation of the hot-extruded GH4151 alloy. In addition, the step-shaped structures can be observed at grain boundaries, which ensure the low-energy surface state during the DRX process.

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Section: Resultsmentioning

confidence: 99%

Investigation on Sub-Solvus Recrystallization Mechanisms in an Advanced γ-γ’ Nickel-Based Superalloy GH4151

Chen

et al. 2020

Materials

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“…Some substructures formed by low-angle grain boundaries can be seen in the pre-existing grains, as shown in Figure 8a. In addition, a number of necklace-like structures are also observed, which are reported to be facilitated by continuous dynamic recrystallization (CDRX) [39][40][41]. Figure 9 indicates the location misorientation (black lines) and cumulative misorientation (red line) along the AB and CD lines, respectively.…”

Section: Microstructure Analysismentioning

confidence: 97%

Characterization of Hot Deformation Behavior and Processing Maps of Mg-3Sn-2Al-1Zn-5Li Magnesium Alloy

Guo

Xuanyuan

Lia

et al. 2019

Metals

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The dynamic microstructure evolution of Mg-3Sn-2Al-1Zn-5Li magnesium alloy during hot deformation is studied by hot compression tests over the temperature range of 200–350 °C under the strain rate of 0.001–1 s−1, whereafter constitutive equations and processing maps are developed and constructed. In most of cases, the material shows typical dynamic recrystallization (DRX) features, with a signal peak value followed by a gradual decrease. The value of Q (deformation activation energy) is 138.89414 kJ/mol, and the instability domains occur at high strain rate but the stability domains are opposite, and the optimum hot working parameter for the studied alloy is determined to be 350 °C/0.001 s−1 according to the processing maps. Within 200–350 °C, the operating mechanism of dynamic recrystallization (DRX) of Mg-3Sn-2Al-1Zn-5Li alloy during hot deformation is mainly affected by strain rate. Dynamic recrystallization (DRX) structures are observed from the samples at 300 °C/0.001 s−1 and 350 °C/0.001 s−1, which consist of continuous DRX (CDRX) and discontinuous DRX (DDRX). However, dynamic recovery (DRV) still dominates the softening mechanism. At the grain boundaries, mass dislocation pile-ups and dislocation tangle provide sites for potential nucleation. Meanwhile, flow localization bands are observed from the samples at 200 °C/1 s−1 and 250 °C/0.1 s−1 as the main instability mechanism.

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“…It is commonly accepted that the DDRX nucleation mechanism, characterized by progressive GB bulging, occurrs at high temperature and strain rate. [1,5,8,13,15] As shown in Figure 7a, many tiny DRX grains are interspersed with some bulged GBs. The bulging GBs usually possess high local orientation or strain gradients, and, thus, are potential sites for DDRX nucleation.…”

Section: Microstructural Observation and Crack Characterizationmentioning

confidence: 99%

“…Some reports have been conducted on the mechanisms of DRX, where two mechanisms are generally accepted: discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX). [10][11][12][13][14][15] Previous research [16][17][18][19][20][21][22] demonstrated that DDRX via grain boundary (GB) bulging dominates the DRX process during the deformation of several nickel-based superalloys, such as Allvac 718Plus, Udimet 720Li, FGH4096, Inconel 718, and so on. DDRX strongly depends on preexisting GBs, which are potential nucleation sites of DDRX.…”

Section: Introductionmentioning

confidence: 99%

“…Reports on the DRX behavior of superalloys have been studied in detail. Some reports have been conducted on the mechanisms of DRX, where two mechanisms are generally accepted: discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) . Previous research demonstrated that DDRX via grain boundary (GB) bulging dominates the DRX process during the deformation of several nickel‐based superalloys, such as Allvac 718Plus, Udimet 720Li, FGH4096, Inconel 718, and so on.…”

Section: Introductionmentioning

confidence: 99%

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A Mechanism for the Evolution of Hot Compression Cracking in Inconel 625 Alloy Ingot With Respect to Grain Growth

Jia

Gao

Ji³

2020

Adv Eng Mater

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Hot compression cracking of as‐cast Inconel 625 alloy is investigated utilizing high temperature and high strain rate compression tests. The formation mechanism of the hot crack is systematically investigated based on grain growth and crystal slipping. Scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) analysis are used to characterize the crack morphology and microstructure. SEM results showed that the hot cracking during hot compression of Inconel 625 alloy is determined to be quasi‐cleavage fracture. The formation of carbide (NbC) plays a key role in the formation and propagation of the hot crack. The various slip systems activation strongly contributes to the overall growth of the dynamic recrystallization (DRX) grains. In addition, subgranular boundary formation within the grown grains is attribution to various slip systems activation in different local regions. The initiation and propagation of the hot compression cracks in Inconel 625 alloy depend on the development of the subgranular boundary within the grown grain.

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DDRX and CDRX of an as-cast nickel-based superalloy during hot compression at γ′ sub-/super-solvus temperatures

Cited by 88 publications

References 64 publications

Investigation on Sub-Solvus Recrystallization Mechanisms in an Advanced γ-γ’ Nickel-Based Superalloy GH4151

Investigation on Sub-Solvus Recrystallization Mechanisms in an Advanced γ-γ’ Nickel-Based Superalloy GH4151

Characterization of Hot Deformation Behavior and Processing Maps of Mg-3Sn-2Al-1Zn-5Li Magnesium Alloy

A Mechanism for the Evolution of Hot Compression Cracking in Inconel 625 Alloy Ingot With Respect to Grain Growth

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