A high performance Ni-Al-Mo-B system cast Ni_3Al base alloy, named Alloy IC6, has been developed for advanced gas turbine blades and vanes. The alloy has high strength and ductility from room temperature to 1100℃ as...A high performance Ni-Al-Mo-B system cast Ni_3Al base alloy, named Alloy IC6, has been developed for advanced gas turbine blades and vanes. The alloy has high strength and ductility from room temperature to 1100℃ as well as excellent creep resistance over a wide temperature range of 760℃ to 1100℃ . The superior mechanical properties of this alloy.may be attributed to (1) solid solution hardening by the large amount of Mo addition , (2)second phase strengthening by γ-phase and other minor phases that precipitate in various temperature ranges, (3) rearrangement of γ-phase in the form of raft structure during creep deformation , (4) high-density misfit dislocation networks at the γ /γ' interfaces that form due to a high value ofγ /γ ' misfit .展开更多
The effect of recycle proportion on the composition,microstructure and mechanical prop- erites of recycled Ni_3Al basealloy IC6 was examined by scanning electron microscopy with X-ray en-ergy-dispersive spectrometer (...The effect of recycle proportion on the composition,microstructure and mechanical prop- erites of recycled Ni_3Al basealloy IC6 was examined by scanning electron microscopy with X-ray en-ergy-dispersive spectrometer (SEM/ES) and transmission electronmicroscopy (TEM). The results indicate that the addition of recycledscraps has no obvious effect on the chemical composition, except thecontent of C and N increases with the addition proportion of recycledscraps. The microstructure of IC6 recycled alloys has no obviousdifference compared with the fresh alloy, except some M_6C car- bidesprecipitate in the interdendritic area.展开更多
The HAZ cracking test in EB welding condition and hot ductility test show that the cracking mechanism is the formation of Ni - Ni5Zr eutectic which is resulting from the enrichment of Zr in grain boundaries during ...The HAZ cracking test in EB welding condition and hot ductility test show that the cracking mechanism is the formation of Ni - Ni5Zr eutectic which is resulting from the enrichment of Zr in grain boundaries during welding.In order to eliminate HAZ cracks the diffusion and recrystalization anealing treatment after cast and during cold rolling should be conducted in vacuum or protecting atmosphere and at the same time a slow welding speed is necessary.展开更多
The electronic structure of Ni_3Al alloys with different B contents has been investigated by measuring the positron lifetime spectra.The segregation of B atoms to defects could form strong covalent bondings with Ni an...The electronic structure of Ni_3Al alloys with different B contents has been investigated by measuring the positron lifetime spectra.The segregation of B atoms to defects could form strong covalent bondings with Ni and Al atoms and make the electronic structure in those locations similar to that in bulk,thus strengthen their cohesion.The interaction of B atoms,which were solid-solutioned in the crystal lattice of Ni_3Al in a manner of occupying interstitial sites,with Ni and Al atoms resulted in the increase of the density of valent electrons,thus increased the bonding cohesion in bulk.The im- provement of the mechanical properties of Ni_3Al alloys by B doping was due to both“grain bounda- ry effect”and“bulk effect”of B,which correlated with their electronic structure.展开更多
In this paper, Ni-Cr-Al-Y-Si coating deposited by vacuum are deposition on the Ni_3Alalloy IC6, the typical use of which is for turbine blades and vanes, was examined.The results of the tests show that the tensile pro...In this paper, Ni-Cr-Al-Y-Si coating deposited by vacuum are deposition on the Ni_3Alalloy IC6, the typical use of which is for turbine blades and vanes, was examined.The results of the tests show that the tensile properties at room temperature and stress rupture properties at 1100℃ of the IC6 alloy were not obviously influenced by the coatings. At annealing state, limited element interdiffusion was observed. After stress rupture testing for 252 h at 1100℃/90 MPa, however,significant interdiffusion of Mo, Cr and Al took place between the coating layer and the substrate.The element diffustion did not result in the formation of brittle phases on the coating/substrate interface. No cracking and spallation in the coating were found.Therefore it can be concluded that the Ni-Cr-Al-Y-Si overlay coating was successful for protecting the IC6 alloy.展开更多
The infiuence of cerium on grnin boundaries of polycrpstalline N3Al alloys has beenstudied. The ja6mcability of a Ce-doped N3Al alloy strongly depends on the certumcontent. The alloy exhibits very poor fabrica6ility a...The infiuence of cerium on grnin boundaries of polycrpstalline N3Al alloys has beenstudied. The ja6mcability of a Ce-doped N3Al alloy strongly depends on the certumcontent. The alloy exhibits very poor fabrica6ility and cannot be fabrtcated into goodsheet8 by cold rolling when the concentmtion of cerium is <0. 0088wt% or>0.044wt%.A 0.011wt%Ce-doped N3Al alloy exhibits relatively good fabricability and may be fab-ricated into useful sheets by repeated cold rolling with 1OOa C annealing. The ductilityof the alloy strongly depends on the cerium distribution. Wthout the grain boundaryprecipitation of a second phase containing cer1um) the higher the segmpation level ofcerzum, the 6ettcr the tensile properties of the alloys, and in turn the more enhancedthe grain boundary cohesion.展开更多
A Zr-rich phase,Ni_5Zr,with low melting point has been fouhd in an Ni_3Al alloy doped with Zr(1.2at.-%).It will cause the incipient melt of the alloy after being homogenized at 1300℃. This makes it difficult to homog...A Zr-rich phase,Ni_5Zr,with low melting point has been fouhd in an Ni_3Al alloy doped with Zr(1.2at.-%).It will cause the incipient melt of the alloy after being homogenized at 1300℃. This makes it difficult to homogenize the coarse casting structures completely and limits the further improvement of properties of the Ni_3Al alloy.展开更多
The calculation of electronic structure of γ'-Ni_3Al phase with or without Mg and W by the Recursion and LCAO methods clarified that Mg and W atoms lose their outer electrons par- tially after they entered γ'...The calculation of electronic structure of γ'-Ni_3Al phase with or without Mg and W by the Recursion and LCAO methods clarified that Mg and W atoms lose their outer electrons par- tially after they entered γ'-Ni_3Al.It causes the reduction of the radii of the atoms.So it is preferable for Mg atom to enter γ'-phase by the substitution.The interaction between Mg and γ'-phase matrix may be strengthened and a more stable structure of γ'-phase may be formed while Mg and W entered γ'-Ni_3Al simultaneously.展开更多
The Ni_(3)Al-based alloy has been considered as a robust catalyst for oxygen evolution reaction(OER)due to its long-term durability and acceptable activity.However,related reports about understanding the catalytic mec...The Ni_(3)Al-based alloy has been considered as a robust catalyst for oxygen evolution reaction(OER)due to its long-term durability and acceptable activity.However,related reports about understanding the catalytic mechanism are rare and desirable.Herein,the effect of γ/γ’phase lattice mismatch on the catalytic performance caused by various cooling rates after solution heat treatment was investigated.With decreasing cooling rate,the morphologies of γ' precipitates transformed from sphere to cube and the lattice mismatch increased from-0.172%to-0.409%.The increased lattice mismatch facilitated the formation of the active β-NiOOH phase and enhanced the intrinsic catalytic activity,resulting in the optimized OER overpotential of 240 mV at a current density of 10 mA cm^(−2) with a Tafel slope of 66.1 mV dec^(−1) and a stability of 200 h in 1 M KOH.This work reveals the lattice mismatch effect on OER and provides a potential candidate for OER.展开更多
Antiphase boundaries(APBs)are planar defects that play a critical role in strengthening Ni-based superalloys,and their sensitivity to alloy composition offers a flexible tuning parameter for alloy design.Here,we repor...Antiphase boundaries(APBs)are planar defects that play a critical role in strengthening Ni-based superalloys,and their sensitivity to alloy composition offers a flexible tuning parameter for alloy design.Here,we report a computational workflow to enable the development of sufficient data to train machine-learning(ML)models to automate the study of the effect of composition on the(111)APB energy in Ni_(3)Al-based alloys.We employ ML to leverage this wealth of data and identify several physical properties that are used to build predictive models for the APB energy that achieve a cross-validation error of 0.033 J m^(−2).We demonstrate the transferability of these models by predicting APB energies in commercial superalloys.Moreover,our use of physically motivated features such as the ordering energy and stoichiometry-based features opens the way to using existing materials properties databases to guide superalloy design strategies to maximize the APB energy.展开更多
文摘A high performance Ni-Al-Mo-B system cast Ni_3Al base alloy, named Alloy IC6, has been developed for advanced gas turbine blades and vanes. The alloy has high strength and ductility from room temperature to 1100℃ as well as excellent creep resistance over a wide temperature range of 760℃ to 1100℃ . The superior mechanical properties of this alloy.may be attributed to (1) solid solution hardening by the large amount of Mo addition , (2)second phase strengthening by γ-phase and other minor phases that precipitate in various temperature ranges, (3) rearrangement of γ-phase in the form of raft structure during creep deformation , (4) high-density misfit dislocation networks at the γ /γ' interfaces that form due to a high value ofγ /γ ' misfit .
文摘The effect of recycle proportion on the composition,microstructure and mechanical prop- erites of recycled Ni_3Al basealloy IC6 was examined by scanning electron microscopy with X-ray en-ergy-dispersive spectrometer (SEM/ES) and transmission electronmicroscopy (TEM). The results indicate that the addition of recycledscraps has no obvious effect on the chemical composition, except thecontent of C and N increases with the addition proportion of recycledscraps. The microstructure of IC6 recycled alloys has no obviousdifference compared with the fresh alloy, except some M_6C car- bidesprecipitate in the interdendritic area.
文摘The HAZ cracking test in EB welding condition and hot ductility test show that the cracking mechanism is the formation of Ni - Ni5Zr eutectic which is resulting from the enrichment of Zr in grain boundaries during welding.In order to eliminate HAZ cracks the diffusion and recrystalization anealing treatment after cast and during cold rolling should be conducted in vacuum or protecting atmosphere and at the same time a slow welding speed is necessary.
文摘The electronic structure of Ni_3Al alloys with different B contents has been investigated by measuring the positron lifetime spectra.The segregation of B atoms to defects could form strong covalent bondings with Ni and Al atoms and make the electronic structure in those locations similar to that in bulk,thus strengthen their cohesion.The interaction of B atoms,which were solid-solutioned in the crystal lattice of Ni_3Al in a manner of occupying interstitial sites,with Ni and Al atoms resulted in the increase of the density of valent electrons,thus increased the bonding cohesion in bulk.The im- provement of the mechanical properties of Ni_3Al alloys by B doping was due to both“grain bounda- ry effect”and“bulk effect”of B,which correlated with their electronic structure.
文摘In this paper, Ni-Cr-Al-Y-Si coating deposited by vacuum are deposition on the Ni_3Alalloy IC6, the typical use of which is for turbine blades and vanes, was examined.The results of the tests show that the tensile properties at room temperature and stress rupture properties at 1100℃ of the IC6 alloy were not obviously influenced by the coatings. At annealing state, limited element interdiffusion was observed. After stress rupture testing for 252 h at 1100℃/90 MPa, however,significant interdiffusion of Mo, Cr and Al took place between the coating layer and the substrate.The element diffustion did not result in the formation of brittle phases on the coating/substrate interface. No cracking and spallation in the coating were found.Therefore it can be concluded that the Ni-Cr-Al-Y-Si overlay coating was successful for protecting the IC6 alloy.
文摘The infiuence of cerium on grnin boundaries of polycrpstalline N3Al alloys has beenstudied. The ja6mcability of a Ce-doped N3Al alloy strongly depends on the certumcontent. The alloy exhibits very poor fabrica6ility and cannot be fabrtcated into goodsheet8 by cold rolling when the concentmtion of cerium is <0. 0088wt% or>0.044wt%.A 0.011wt%Ce-doped N3Al alloy exhibits relatively good fabricability and may be fab-ricated into useful sheets by repeated cold rolling with 1OOa C annealing. The ductilityof the alloy strongly depends on the cerium distribution. Wthout the grain boundaryprecipitation of a second phase containing cer1um) the higher the segmpation level ofcerzum, the 6ettcr the tensile properties of the alloys, and in turn the more enhancedthe grain boundary cohesion.
文摘A Zr-rich phase,Ni_5Zr,with low melting point has been fouhd in an Ni_3Al alloy doped with Zr(1.2at.-%).It will cause the incipient melt of the alloy after being homogenized at 1300℃. This makes it difficult to homogenize the coarse casting structures completely and limits the further improvement of properties of the Ni_3Al alloy.
文摘The calculation of electronic structure of γ'-Ni_3Al phase with or without Mg and W by the Recursion and LCAO methods clarified that Mg and W atoms lose their outer electrons par- tially after they entered γ'-Ni_3Al.It causes the reduction of the radii of the atoms.So it is preferable for Mg atom to enter γ'-phase by the substitution.The interaction between Mg and γ'-phase matrix may be strengthened and a more stable structure of γ'-phase may be formed while Mg and W entered γ'-Ni_3Al simultaneously.
基金financially supported by the National Natural Science Foundation of China (Nos.52034004 and 52075373)。
文摘The Ni_(3)Al-based alloy has been considered as a robust catalyst for oxygen evolution reaction(OER)due to its long-term durability and acceptable activity.However,related reports about understanding the catalytic mechanism are rare and desirable.Herein,the effect of γ/γ’phase lattice mismatch on the catalytic performance caused by various cooling rates after solution heat treatment was investigated.With decreasing cooling rate,the morphologies of γ' precipitates transformed from sphere to cube and the lattice mismatch increased from-0.172%to-0.409%.The increased lattice mismatch facilitated the formation of the active β-NiOOH phase and enhanced the intrinsic catalytic activity,resulting in the optimized OER overpotential of 240 mV at a current density of 10 mA cm^(−2) with a Tafel slope of 66.1 mV dec^(−1) and a stability of 200 h in 1 M KOH.This work reveals the lattice mismatch effect on OER and provides a potential candidate for OER.
基金This work is partly performed under the auspices of the U.S.Department of Energy(DOE)by the Lawrence Livermore National Laboratory(LLNL)under Contract No.DE-AC52-07NA27344The authors are grateful for project funding from the High-Performance Computing for Materials(HPC4Mtls)Program of the DOE Vehicle Technologies Office under Cooperative Research and Development Agreement(CRADA)No.TC02309+2 种基金Computing support for this work comes from the LLNL Institutional Computing facilities,and the National Energy Research Scientific Computing Center(NERSC),a DOE Office of Science User Facility operated under Contract No.DE-AC02-05-CH11231E.C.acknowledges a fellowship through the National Science Foundation Graduate Research Fellowship Program under Grant No.DGE-1752814M.A.acknowledges support for his contributions by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,Materials Sciences and Engineering Division,under Contract No.DE-AC02-05-CH11231 within the Materials Project program(KC23MP).All figures are produced using matplotlib79.
文摘Antiphase boundaries(APBs)are planar defects that play a critical role in strengthening Ni-based superalloys,and their sensitivity to alloy composition offers a flexible tuning parameter for alloy design.Here,we report a computational workflow to enable the development of sufficient data to train machine-learning(ML)models to automate the study of the effect of composition on the(111)APB energy in Ni_(3)Al-based alloys.We employ ML to leverage this wealth of data and identify several physical properties that are used to build predictive models for the APB energy that achieve a cross-validation error of 0.033 J m^(−2).We demonstrate the transferability of these models by predicting APB energies in commercial superalloys.Moreover,our use of physically motivated features such as the ordering energy and stoichiometry-based features opens the way to using existing materials properties databases to guide superalloy design strategies to maximize the APB energy.
