This study documents laboratory-scale observation of the interactions between the Ni-based superalloy FGH4096 and refractories.Three different crucibles were tested—MgO,Al2O3,and MgO–spinel.We studied the variations...This study documents laboratory-scale observation of the interactions between the Ni-based superalloy FGH4096 and refractories.Three different crucibles were tested—MgO,Al2O3,and MgO–spinel.We studied the variations in the compositions of the inclusions and the alloy–crucible interface with the reaction time using scanning electron microscopy equipped with energy dispersive X-ray spectroscopy and Xray diffraction.The results showed that the MgO and MgO–spinel crucibles form MgO-containing inclusions(Al–Mg oxides and Al–Mg–Ti oxides),whereas the inclusions formed when using the Al2O3 crucible are Al2O3 and Al–Ti oxides.We observed a new MgAl2O4 phase at the inner wall of the MgO crucible,with the alloy melted in the MgO crucible exhibiting fewer inclusions.No new phase occurred at the inner wall of the Al2O3 crucible.We discuss the mechanism of interaction between the refractories and the Ni-based superalloy.Physical erosion was found to predominate in the Al2O3 crucible,whereas dissolution and chemical reactions dominated in the MgO crucible.No reaction was observed between three crucibles and the Ti of the melt although the Ti content(3.8wt%)was higher than that of Al(2.1wt%).展开更多
The denitrogenation and desulphurization behavior during vacuum induction melting (VIM) refining Ni base superalloy using CaO crucible was studied. It has been found that the desulphurization process did not occur by ...The denitrogenation and desulphurization behavior during vacuum induction melting (VIM) refining Ni base superalloy using CaO crucible was studied. It has been found that the desulphurization process did not occur by only using CaO crucible. Combining with the results of XRD and composition analysis, the desulphurization mechanism of CaO crucible was proposed. Al addition limits effect on denitrogenation, but it is very important for desulphurization. Ti addition has adverse effect on denitrogenation. The increase of vacuum is a powerful measurement to accelerate the denitrogenation process.展开更多
In this study,yttrium as desulfurizer on the purification of Ni-20Co-20Cr-10Al-Y alloy during vac-uum induction melting(VIM)process using Y_(2)O_(3)cru-cibles was investigated experimentally.It is found that Y plays a...In this study,yttrium as desulfurizer on the purification of Ni-20Co-20Cr-10Al-Y alloy during vac-uum induction melting(VIM)process using Y_(2)O_(3)cru-cibles was investigated experimentally.It is found that Y plays an important role on the desulfurizing of the NiCo-CrAIY alloy.Without any addition of Y,merely the employment of Y_(2)O_(3)crucibles could effectively reduce S content of the alloy melts from 28×10^(-6)to 6×10^(-6)-7×10^(-6).With addition of 0.8 wt%Y in the alloy,the concentration of S could further reduce 2×10^(7)3×10^(-6).The primary interactive mechanism between Y and molten alloy was concluded to be the synthesis reac-tion of NisY phase,Y2S3 phases and YAIO_(3)phase.In the desulfurize slags,Y2S3 phases and Y_(2)O_(3)phase are found.No secondary contamination is present in the alloy melts after addition of Y.展开更多
基金This work is financially supported by the Natural Science Foundation of China(No.51974029)the Natural Science and Technology Major Project(No.2017-VI-0014-0086)and Fundamental Research Funds for the Central Universities(Nos.FRF-AT-19-013 and FRF-NP-19-003).
文摘This study documents laboratory-scale observation of the interactions between the Ni-based superalloy FGH4096 and refractories.Three different crucibles were tested—MgO,Al2O3,and MgO–spinel.We studied the variations in the compositions of the inclusions and the alloy–crucible interface with the reaction time using scanning electron microscopy equipped with energy dispersive X-ray spectroscopy and Xray diffraction.The results showed that the MgO and MgO–spinel crucibles form MgO-containing inclusions(Al–Mg oxides and Al–Mg–Ti oxides),whereas the inclusions formed when using the Al2O3 crucible are Al2O3 and Al–Ti oxides.We observed a new MgAl2O4 phase at the inner wall of the MgO crucible,with the alloy melted in the MgO crucible exhibiting fewer inclusions.No new phase occurred at the inner wall of the Al2O3 crucible.We discuss the mechanism of interaction between the refractories and the Ni-based superalloy.Physical erosion was found to predominate in the Al2O3 crucible,whereas dissolution and chemical reactions dominated in the MgO crucible.No reaction was observed between three crucibles and the Ti of the melt although the Ti content(3.8wt%)was higher than that of Al(2.1wt%).
文摘The denitrogenation and desulphurization behavior during vacuum induction melting (VIM) refining Ni base superalloy using CaO crucible was studied. It has been found that the desulphurization process did not occur by only using CaO crucible. Combining with the results of XRD and composition analysis, the desulphurization mechanism of CaO crucible was proposed. Al addition limits effect on denitrogenation, but it is very important for desulphurization. Ti addition has adverse effect on denitrogenation. The increase of vacuum is a powerful measurement to accelerate the denitrogenation process.
基金This study was financially supported by the National Science&Technology Pillar Program of China(No.2013BAB11B04)the National Natural Science Foundation of China(No.51404017)Furthermore,the authors wish to express their appreciation to the State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology.
文摘In this study,yttrium as desulfurizer on the purification of Ni-20Co-20Cr-10Al-Y alloy during vac-uum induction melting(VIM)process using Y_(2)O_(3)cru-cibles was investigated experimentally.It is found that Y plays an important role on the desulfurizing of the NiCo-CrAIY alloy.Without any addition of Y,merely the employment of Y_(2)O_(3)crucibles could effectively reduce S content of the alloy melts from 28×10^(-6)to 6×10^(-6)-7×10^(-6).With addition of 0.8 wt%Y in the alloy,the concentration of S could further reduce 2×10^(7)3×10^(-6).The primary interactive mechanism between Y and molten alloy was concluded to be the synthesis reac-tion of NisY phase,Y2S3 phases and YAIO_(3)phase.In the desulfurize slags,Y2S3 phases and Y_(2)O_(3)phase are found.No secondary contamination is present in the alloy melts after addition of Y.
