The pre-precipitation processes of γ＇ phase in Ni-Al-Ti alloy with different chemical compositions are investigated by microscopic phase-field dynamics model. The simulation results show that the early precip...The pre-precipitation processes of γ＇ phase in Ni-Al-Ti alloy with different chemical compositions are investigated by microscopic phase-field dynamics model. The simulation results show that the early precipitated phase with L10 structure is formed before the formation of γ＇ phase. With the increase of Al content, the composition of precipitated phase is transformed from the co-existence of γ＇ phase and material phase into single y phase. Furthermore, excessive Al content can stimulate the production of γ＇ phase, and the conversion time from L10 phase to L12 phase will lag behind other samples with lower Al con-tent. By analyzing the occupation probability of Ti, it can be found that the solid solution strengthening effect of Ti is reduced with the increase of Al component.展开更多
利用金相和 SEM 显微组织分析技术,示差扫描量热法(DSC)和振动磁力计(VSM)考察了 Ni_(52)Ga_(28)Fe_(20-x)Co_x 合金中 Co 元素含量 x 对马氏体相变和铁磁性转变的影响,用粉末 X 射线衍射方法(XRD)分析马氏体相的结构类型．在x(?)6 的...利用金相和 SEM 显微组织分析技术,示差扫描量热法(DSC)和振动磁力计(VSM)考察了 Ni_(52)Ga_(28)Fe_(20-x)Co_x 合金中 Co 元素含量 x 对马氏体相变和铁磁性转变的影响,用粉末 X 射线衍射方法(XRD)分析马氏体相的结构类型．在x(?)6 的范围内 Co 代替 Fe 能够显著提高 Ni_(52)Ga_(28)Fe_(20-x)Co_x 合金的马氏体相变温度,对铁磁性转变 Curie 点的影响不大．x 每增加1可以使马氏体相变温度提高50—60K．低温淬火(773K/1h)对 Ni_(52)Ga_(28)Fe_(20-x)Co_x 合金马氏体相变温度的影响不大,但使合金的 Curie 点提高20—30 K．粉末 XRD 分析表明该合金系列经1423和773K 两种温度处理后都只出现 L1_0(2M)马氏体．展开更多
The microstructural features, shape memory behavior and mechanical properties of Ni-Mn based alloys were investigated by differential scanning calorimetry （DSC）, scanning electron microscopy （SEM）, transmission el...The microstructural features, shape memory behavior and mechanical properties of Ni-Mn based alloys were investigated by differential scanning calorimetry （DSC）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and thermal cycling test under various stresses. The transformation temperatures shifted toward lower temperatures when adding a third element into the Ni-Mn system. The addition of 10 at. pct Fe increased considerably the mechanical properties exhibiting still high transformation temperatures. However, it was found that in NiMn40Fe10 alloy the martensitic transformation is not thermoelastic in nature. The mechanism of this transformation and the crystallography of Ni-Mn（50-x）-Fex （x=5, 7, 10, 20 at. pct） alloys are presented.展开更多
(FePt)85Cu15 nanoparticles were successfully prepared by alternate reduction of metal salts in aqueous medium.Detailed investigations on the correlation between the magnetic and structural properties of these nanopart...(FePt)85Cu15 nanoparticles were successfully prepared by alternate reduction of metal salts in aqueous medium.Detailed investigations on the correlation between the magnetic and structural properties of these nanoparticles are presented as a function of annealing temperature.Both the X-ray diffraction patterns and the magnetic hysteresis loop measurements show the existence of L10-FePt phase at a relative low annealing temperature.It is proved that the Cu additive and alternate reduction are very effective methods in reducing the ordering temperature of FePt nanoparticles.展开更多
The phase transformation and magnetic hysteresis properties of melt-spun Fe41 Pd41 B8 Si6 P4 ribbons subjected to the annealing at temperatures of 500-550℃were studied after holding for 0.1-60.0 h by transmission ele...The phase transformation and magnetic hysteresis properties of melt-spun Fe41 Pd41 B8 Si6 P4 ribbons subjected to the annealing at temperatures of 500-550℃were studied after holding for 0.1-60.0 h by transmission electron microscopy(TEM),X-ray diffraction(XRD)and thermomagnetic analysis.The additions of P,B and Si to the FePd alloy allowed us to achieve the coercivity of124 kA·m-1,which is 2.6 times higher than that of the melt-spun ribbons of the binary equiatomic FePd alloy.The high-coercivity Fe41Pd41B8 Si6 P4 alloy is nanocrystalline and is composed of the ordered L10-phase grains approximately 40 nm in size and inclusions of the Fe2(P,B)and Pd2(Si,B)phases.The coercivity kinetics is controlled by the phase transformation which can be divided into three stages:transformation from the bcc structure to nanosized regions of the fee and Fe2 P phases;transformation from the fee to L10 nanosized regions with somewhat different degrees of tetragonality and their ordering;and extensive growth of the weight fraction of L10 phase from the fee nanosized regions.P and B atoms occupy interstitial sites in the iron plane of L10 lattice,thus decreasing its Curie temperature(TC).展开更多
基金National Natural Science Foundation of China(Nos.U1610123,51674226,51574207,51574206,51274175)International Cooperation Project of the Ministry of Science and Technology of China(No.2014DFA50320)Science and Technology Major Project of Shanxi Province(No.MC2016-06)
文摘The pre-precipitation processes of γ＇ phase in Ni-Al-Ti alloy with different chemical compositions are investigated by microscopic phase-field dynamics model. The simulation results show that the early precipitated phase with L10 structure is formed before the formation of γ＇ phase. With the increase of Al content, the composition of precipitated phase is transformed from the co-existence of γ＇ phase and material phase into single y phase. Furthermore, excessive Al content can stimulate the production of γ＇ phase, and the conversion time from L10 phase to L12 phase will lag behind other samples with lower Al con-tent. By analyzing the occupation probability of Ti, it can be found that the solid solution strengthening effect of Ti is reduced with the increase of Al component.
文摘利用金相和 SEM 显微组织分析技术,示差扫描量热法(DSC)和振动磁力计(VSM)考察了 Ni_(52)Ga_(28)Fe_(20-x)Co_x 合金中 Co 元素含量 x 对马氏体相变和铁磁性转变的影响,用粉末 X 射线衍射方法(XRD)分析马氏体相的结构类型．在x(?)6 的范围内 Co 代替 Fe 能够显著提高 Ni_(52)Ga_(28)Fe_(20-x)Co_x 合金的马氏体相变温度,对铁磁性转变 Curie 点的影响不大．x 每增加1可以使马氏体相变温度提高50—60K．低温淬火(773K/1h)对 Ni_(52)Ga_(28)Fe_(20-x)Co_x 合金马氏体相变温度的影响不大,但使合金的 Curie 点提高20—30 K．粉末 XRD 分析表明该合金系列经1423和773K 两种温度处理后都只出现 L1_0(2M)马氏体．
基金express their gratitude to the Ministry of Education,Culture and Sports of Japan(MEXT) for partially supporting this research
文摘The microstructural features, shape memory behavior and mechanical properties of Ni-Mn based alloys were investigated by differential scanning calorimetry （DSC）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and thermal cycling test under various stresses. The transformation temperatures shifted toward lower temperatures when adding a third element into the Ni-Mn system. The addition of 10 at. pct Fe increased considerably the mechanical properties exhibiting still high transformation temperatures. However, it was found that in NiMn40Fe10 alloy the martensitic transformation is not thermoelastic in nature. The mechanism of this transformation and the crystallography of Ni-Mn（50-x）-Fex （x=5, 7, 10, 20 at. pct） alloys are presented.
基金supported by the National Key Research and Development Program(2016YFB1100101)the National Natural Science Foundation of China(51471135)+1 种基金Shaanxi Science and Technology Program(2017KW-ZD-07)Shenzhen Fundamental Research Program.
文摘(FePt)85Cu15 nanoparticles were successfully prepared by alternate reduction of metal salts in aqueous medium.Detailed investigations on the correlation between the magnetic and structural properties of these nanoparticles are presented as a function of annealing temperature.Both the X-ray diffraction patterns and the magnetic hysteresis loop measurements show the existence of L10-FePt phase at a relative low annealing temperature.It is proved that the Cu additive and alternate reduction are very effective methods in reducing the ordering temperature of FePt nanoparticles.
基金financially supported by the Indian-Russian Collaborative Project(Nos.17-52-45097 and INT/RUS/RFBR/P-267)the State Assignment of Ministry of Science and Education of Russia(No.AAAA-A18-118020290129-5).
文摘The phase transformation and magnetic hysteresis properties of melt-spun Fe41 Pd41 B8 Si6 P4 ribbons subjected to the annealing at temperatures of 500-550℃were studied after holding for 0.1-60.0 h by transmission electron microscopy(TEM),X-ray diffraction(XRD)and thermomagnetic analysis.The additions of P,B and Si to the FePd alloy allowed us to achieve the coercivity of124 kA·m-1,which is 2.6 times higher than that of the melt-spun ribbons of the binary equiatomic FePd alloy.The high-coercivity Fe41Pd41B8 Si6 P4 alloy is nanocrystalline and is composed of the ordered L10-phase grains approximately 40 nm in size and inclusions of the Fe2(P,B)and Pd2(Si,B)phases.The coercivity kinetics is controlled by the phase transformation which can be divided into three stages:transformation from the bcc structure to nanosized regions of the fee and Fe2 P phases;transformation from the fee to L10 nanosized regions with somewhat different degrees of tetragonality and their ordering;and extensive growth of the weight fraction of L10 phase from the fee nanosized regions.P and B atoms occupy interstitial sites in the iron plane of L10 lattice,thus decreasing its Curie temperature(TC).
