The influences of initial microstructures on the mechanical properties and the recrystallization texture of magnetostrictive 0.1 at% Nb C-doped Fe83 Ga17 alloys were investigated. The directionally solidified columnar...The influences of initial microstructures on the mechanical properties and the recrystallization texture of magnetostrictive 0.1 at% Nb C-doped Fe83 Ga17 alloys were investigated. The directionally solidified columnar-grained structure substantially enhanced the tensile elongation at intermediate temperatures by suppressing fracture along the transverse boundaries. Compared with tensile elongations of 1.0% at 300℃ and 12.0% at 500℃ of the hot-forged equiaxed-grained alloys, the columnar-grained alloys exhibited substantially increased tensile elongations of 21.6% at 300℃ and 46.6% at 500℃. In the slabs for rolling, the introduction of 〈001〉-oriented columnar grains also promotes the secondary recrystallization of Goss grains in the finally annealed sheets, resulting in an improvement of the saturation magnetostriction. For the columnar-grained specimens, the inhomogeneous microstructure and disadvantage in number and size of Goss grains are improved in the primarily annealed sheets, which is beneficial to the abnormal growth of Goss grains during the final annealing process.展开更多
The damping performance of Fe_(83)Ga_(17) alloys has been investigated in the static magnetic field (H). The results demonstrate that the damping peak value can be adjusted between 0.020 and 0.085 under the magnetic f...The damping performance of Fe_(83)Ga_(17) alloys has been investigated in the static magnetic field (H). The results demonstrate that the damping peak value can be adjusted between 0.020 and 0.085 under the magnetic field and reaches a maximum at the critical magnetic field (H_(cr)=0.2 m T). As H is less than H_(cr).展开更多
Pr_(83)Cu_(17)(wt%) grain boundary reconstruction was applied to prepare sintered NdFeB magnets. The effects of addition amount and annealing on the bending strength were investigated. The results show that Pr_(83)Cu_...Pr_(83)Cu_(17)(wt%) grain boundary reconstruction was applied to prepare sintered NdFeB magnets. The effects of addition amount and annealing on the bending strength were investigated. The results show that Pr_(83)Cu_(17) can not only effectively enhance the bending strength, but also change the mechanical anisotropy in two directions parallel and perpendicular to c-axis. The bending strength perpendicular to c-axis reaches 404 MPa in 10 wt% addition magnet, higher than 348 MPa along parallel direction. This change is attributed to the preferred distribution of boundary phases, i.e., ductile(Nd,Pr)-Fe-Cu phase along perpendicular direction to c-axis and(Nd,Pr)-Fe phase along parallel direction. Moreover, the Cu migration during 480 ℃ annealing is found to be related to this boundary phase distribution.展开更多
Nanostructured Ketjen black/Fe_(3)O_(4) core/shell particles have been prepared through a simple one-step hydrothermal method.The microstructure analysis shows that the assynthesized composite particles display a typi...Nanostructured Ketjen black/Fe_(3)O_(4) core/shell particles have been prepared through a simple one-step hydrothermal method.The microstructure analysis shows that the assynthesized composite particles display a typical core/shell structure:the Ketjen black is playing as the core,while a large number of Fe_(3)O_(4) nanoparticles are uniformly attaching to the surface of the Ketjen black and forming the shell.The investigation of the magnetic properties of the nanostructured Ketjen black/Fe_(3)O_(4) core/shell materials reveals that the as-synthesized composite is a typical soft ferromagnetism material.The 40 wt%Ketjen black/Fe_(3)O_(4)-paraffin composites exhibit an excellent reflection loss value of-64.21 dB at a thickness of 2.00 mm,and the broadest effective bandwidth of 4.17 GHz at a thickness of1.50 mm.This work provides a brand-new type of magnetic carbon nanoparticles,defined as Ketjen black/Fe_(3)O_(4)core/shell particles,which are an excellent candidate for high-perform ance electromagnetic wave absorber materials.展开更多
<110> oriented Tb0.27Dy0.73Fe1.95 alloys were studied under different applied compressive prestresses.Larger saturation magnetostriction by 500×10-6 is obtained for the sample under 5 MPa than that under no...<110> oriented Tb0.27Dy0.73Fe1.95 alloys were studied under different applied compressive prestresses.Larger saturation magnetostriction by 500×10-6 is obtained for the sample under 5 MPa than that under no applied stress.To understand the effect of prestress on the magnetostrictive coefficient,differential magnetostrictive coefficient,relative permeability and coercive force were studied in detail.The results show that the maximum differential magnetostrictive coefficient is about 37 x 10-9 m·A-1,about two times that without stress.In addition,the saturation magnetostriction coefficient increases gradually with the stress increasing,while the maximum differential magnetostrictive coefficient decreases.The saturation inductions under different stresses are similar to a value of about 1.1 T.The relative permeability decreases with stress increasing.展开更多
The(Fe_(82)Al_(13.5)Ga_(4.5))_(99.9)(NbC)_(0.1) sheets with strong Goss texture and large magnetostriction were prepared by rolling and isothermal annealing processes.Single Goss grain growth was observed in sheets un...The(Fe_(82)Al_(13.5)Ga_(4.5))_(99.9)(NbC)_(0.1) sheets with strong Goss texture and large magnetostriction were prepared by rolling and isothermal annealing processes.Single Goss grain growth was observed in sheets undergoing isothermal annealing at 1050 ℃ for 1 h using Ar as protecting gas.With annealing time increasing to 8 h at1050℃,a largest magnetostriction of 154×10^(-6) is obtained in sheet and a large λ_(//)(the maximum magnetostriction with magnetic field parallel to rolling direction)of 160×10^(-6) along the rolling direction is also observed.The fact that a λ_(//) of 160×10^(-6) along RD can be achieved with only 4.5 at% Ga in the Fe-18 at%(Al,Ga) sheet is of practical importance.Compared with previous studies in Fe-Al and Fe-Ga sheets,this paper provides a more efficient approach to prepare strong Goss textured sheets.In this way,a slow continuous heating process,sulfur-induced surface energy control and high-temperature annealing above 1200 ℃ are no more necessary.It shows a good prospect for industrial production of high-performance magnetostrictive alloy sheets.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 51501006)State Key Laboratory for Advanced Metals and Materials (No. 2017Z-11)+1 种基金the Fundamental Research Funds for the Central Universities (No. FRF-GF-17-B2)partly supported by a scholarship from the China Scholarship Council
文摘The influences of initial microstructures on the mechanical properties and the recrystallization texture of magnetostrictive 0.1 at% Nb C-doped Fe83 Ga17 alloys were investigated. The directionally solidified columnar-grained structure substantially enhanced the tensile elongation at intermediate temperatures by suppressing fracture along the transverse boundaries. Compared with tensile elongations of 1.0% at 300℃ and 12.0% at 500℃ of the hot-forged equiaxed-grained alloys, the columnar-grained alloys exhibited substantially increased tensile elongations of 21.6% at 300℃ and 46.6% at 500℃. In the slabs for rolling, the introduction of 〈001〉-oriented columnar grains also promotes the secondary recrystallization of Goss grains in the finally annealed sheets, resulting in an improvement of the saturation magnetostriction. For the columnar-grained specimens, the inhomogeneous microstructure and disadvantage in number and size of Goss grains are improved in the primarily annealed sheets, which is beneficial to the abnormal growth of Goss grains during the final annealing process.
基金financially supported by the National Key Research and Development Program of China (No.2021YFB3501403)。
文摘The damping performance of Fe_(83)Ga_(17) alloys has been investigated in the static magnetic field (H). The results demonstrate that the damping peak value can be adjusted between 0.020 and 0.085 under the magnetic field and reaches a maximum at the critical magnetic field (H_(cr)=0.2 m T). As H is less than H_(cr).
基金supported by National Natural Science Foundation of China(51401021)the State Key Laboratory Advanced Metals and Materials(20162-14)
文摘Pr_(83)Cu_(17)(wt%) grain boundary reconstruction was applied to prepare sintered NdFeB magnets. The effects of addition amount and annealing on the bending strength were investigated. The results show that Pr_(83)Cu_(17) can not only effectively enhance the bending strength, but also change the mechanical anisotropy in two directions parallel and perpendicular to c-axis. The bending strength perpendicular to c-axis reaches 404 MPa in 10 wt% addition magnet, higher than 348 MPa along parallel direction. This change is attributed to the preferred distribution of boundary phases, i.e., ductile(Nd,Pr)-Fe-Cu phase along perpendicular direction to c-axis and(Nd,Pr)-Fe phase along parallel direction. Moreover, the Cu migration during 480 ℃ annealing is found to be related to this boundary phase distribution.
基金financially supported by the National Key Research and Development Program of China (No. 2018YFB0905602)a grant from the Major Programs of Central Iron and Steel Research Institute (No.20021730ZD)。
文摘Nanostructured Ketjen black/Fe_(3)O_(4) core/shell particles have been prepared through a simple one-step hydrothermal method.The microstructure analysis shows that the assynthesized composite particles display a typical core/shell structure:the Ketjen black is playing as the core,while a large number of Fe_(3)O_(4) nanoparticles are uniformly attaching to the surface of the Ketjen black and forming the shell.The investigation of the magnetic properties of the nanostructured Ketjen black/Fe_(3)O_(4) core/shell materials reveals that the as-synthesized composite is a typical soft ferromagnetism material.The 40 wt%Ketjen black/Fe_(3)O_(4)-paraffin composites exhibit an excellent reflection loss value of-64.21 dB at a thickness of 2.00 mm,and the broadest effective bandwidth of 4.17 GHz at a thickness of1.50 mm.This work provides a brand-new type of magnetic carbon nanoparticles,defined as Ketjen black/Fe_(3)O_(4)core/shell particles,which are an excellent candidate for high-perform ance electromagnetic wave absorber materials.
基金financially supported by the National High Technology Research and Development Program of China(No.2011AA03A404).
文摘<110> oriented Tb0.27Dy0.73Fe1.95 alloys were studied under different applied compressive prestresses.Larger saturation magnetostriction by 500×10-6 is obtained for the sample under 5 MPa than that under no applied stress.To understand the effect of prestress on the magnetostrictive coefficient,differential magnetostrictive coefficient,relative permeability and coercive force were studied in detail.The results show that the maximum differential magnetostrictive coefficient is about 37 x 10-9 m·A-1,about two times that without stress.In addition,the saturation magnetostriction coefficient increases gradually with the stress increasing,while the maximum differential magnetostrictive coefficient decreases.The saturation inductions under different stresses are similar to a value of about 1.1 T.The relative permeability decreases with stress increasing.
基金financially supported by the National Natural Science Foundation of China (Nos. 51271019 and 51501006)。
文摘The(Fe_(82)Al_(13.5)Ga_(4.5))_(99.9)(NbC)_(0.1) sheets with strong Goss texture and large magnetostriction were prepared by rolling and isothermal annealing processes.Single Goss grain growth was observed in sheets undergoing isothermal annealing at 1050 ℃ for 1 h using Ar as protecting gas.With annealing time increasing to 8 h at1050℃,a largest magnetostriction of 154×10^(-6) is obtained in sheet and a large λ_(//)(the maximum magnetostriction with magnetic field parallel to rolling direction)of 160×10^(-6) along the rolling direction is also observed.The fact that a λ_(//) of 160×10^(-6) along RD can be achieved with only 4.5 at% Ga in the Fe-18 at%(Al,Ga) sheet is of practical importance.Compared with previous studies in Fe-Al and Fe-Ga sheets,this paper provides a more efficient approach to prepare strong Goss textured sheets.In this way,a slow continuous heating process,sulfur-induced surface energy control and high-temperature annealing above 1200 ℃ are no more necessary.It shows a good prospect for industrial production of high-performance magnetostrictive alloy sheets.
