Fe78B13Si9、(Fe0.99Mo0.01)78B13Si9非晶合金的激波晶化实验研究

 研究了Fe₇₈B₁₃Si₉、(Fe_0.99Mo_0.01)₇₈B₁₃Si₉非晶合金的激波晶化行为。激波是由氢-氧爆炸产生的。实验结果表明：激波能使非晶合金在微秒时间内晶化,晶化主相为α-Fe基固溶体,次晶化相为Fe₃Si,且观察到α-Fe基因溶体晶格常数变小。用DTA分析进一步证实：激波晶化是比较完全的,晶化相相当稳定。     

Resistivity and magnetoresistance of Fe80B20 and Fe78B13Si9 amorphous glasses

Summary The electrical resistivity of Fe₈₀B₂₀ and Fe₇₈B₁₃Si₉ amorphous glasses as a function of temperature from 293 K down to 15 K was measured, and it was found to fit quite well with the model given by Cote and Meisel. Comparison between our resistivity measurements of Fe₈₀B₂₀ and others was made, where some differences were found. These resistivity differences are evidence for a variety of amorphous atomic arrangements of the samples. The longitudinal magnetoresistance of Fe₈₀B₂₀ and Fe₇₈B₁₃Si₉ at 293K and 77K was measured in a low magnetic field. The observed magnetoresistance shows a typical field dependence known for ferromagnetic materials.     

Investigation of positron life times in metallic glasses Fe67Co18B14Si1 and Fe4.7Co70.3B10Si15 before and after crystallization

Positron life times in metallic alloys FeCoBSi of amorphous structures and after crystallization were investigated. The hypothesis that in investigated samples positrons annihilate not only with electron-gas electrons but with covalent-bond electrons as well, is put forward.     

Investigation of amorphous and crystalline Sc3Fe alloys

Amorphous Sc₃Fe alloy has been prepared by splat-cooling with levitation melting. The quadrupole splitting distributions for Sc₃Fe were determined from Mössbauer spectra: the zero-field distribution has a Gaussian form. The analysis of Mössbauer spectra taken in applied magnetic field show that both positive and negative signs of principal component (V_z2) of electrical field gradients (EFG) are present. The crystallization process has also been investigated. Heat treatment of the amorphous alloys causes crystallization first into a metastable, and then into the stable phase.     

Nanocrystallization process and ferromagnetic properties of amorphous (Fe0.99Mo0.01)78Si9B13 ribbons

The nanocrystallization process of soft ferromagnetic (Fe_0.99Mo_0.01)₇₈Si₉B₁₃ ribbons has been studied in detail. Microstructural and ferromagnetic properties are examined by transmission electron microscopy (TEM), X-ray diffraction (XRD), Mössbauer spectroscopy (MS), differential scanning calorimetry (DSC) and magnetization measurements. The Curie and crystallization temperatures are determined to be T_C=665 K and T_x=750 K, respectively. The T_x value is in well agreement with DSC measurement results. XRD patterns had shown two metastable phases (Fe₂₃B₆, Fe₃B) which were formed under in situ nanocrystallization process. These metastable phases embedded in the amorphous matrix have a significant effect on magnetic ordering. The ultimate nanocrystalline (NC) phases of α-Fe(Mo, Si) and Fe₂B at optimum annealing temperature had been observed respectively. It is notable that the magnetization of the amorphous phase decreases more rapidly with increasing temperature than those of NC ferromagnetism, which suggest the presence of the distribution of exchange interaction in the amorphous phase or high metalloid contents.     

Annealing embrittlement of Fe78Si9B13 (METGLAS-2605S2)

The ductile to brittle transition that occurs in amorphous Fe₇₈Si₉B₁₃ (METGLAS-2605S2) has been investigated using mechanical measurements over the temperature range 250–370 °C. The fracture toughness values, K _Ic , have been determined for a range of annealing times (5–30 min) and cooling rates of 15–45 °C/min. A pronounced ductile to brittle transition is observed around 310(10) °C although no obvious structural changes are evident as indicated by x-ray diffraction. Comparison of transmission and back-scattered conversion electron ⁵⁷Fe Mössbauer spectra for the bulk as-received ribbon in the ductile state ( $K_{Ic}=52~{\rm MPa} \cdot \sqrt{m}$ ) and the ribbon annealed to the brittle state ( $K_{Ic}\sim10~{\rm MPa} \cdot \sqrt{m}$ ) indicates magnetic texture effects in both the bulk and on the surface of these amorphous ribbons, related to the magnetostriction resulting from the quenched-in stress during the ribbon production process, and the ensuing stress-relief upon annealing.     

Mössbauer Effect Study of Corroded Amorphous Alloy Fe78B13Si9

Mössbauer effect and Scanning Electron Microscopy were used to investigate the effect of immersing the amorphous alloy Fe₇₈B₁₃Si₉ in 3% NaCl solution over different periods and different pH. The results indicated that the average angle of orientation of the magnetic moments had increased with increasing time of immersion and decrease in pH value. The corrosion product was found to be lepidocrocite (γ-FeOOH).     

Magnetic anisotropy of amorphous (Fe1−x Co x )78Si10B12 alloys

In order to better understand the problem of magnetic anisotropy in amorphous alloys produced by a rapidly quenching technique, in-plane magnetic anisotropy of amorphous (Fe_1−x Co _x (₇₈Si₁₀B₁₂ alloys was measured by means of a torque magnetometer using a disk specimen made from the amorphous alloy ribbon. The amorphous ribbons were prepared by a single roller type quenching apparatus. It was found that the anisotropy had mostly twofold symmetry in all the alloy cases, and that the concentrationx dependence of the anisotropy constant behaved differently from that of the magnetostriction. Moreover, the anisotropy did not disappear by subsequent annealing at high temperatures where the internal stress relief and the crystallization were completed.     

Nanoporosity and magnetic performance of Fe58Ni20Si9B13 amorphous metallic alloy

The structure and magnetic properties of this amorphous alloy are studied. The structure was varied by applying a hydrostatic pressure of 10 kbar. By means of small-angle x-ray diffraction analysis, two fractions of nanopores (30 and 140 nm in size) are revealed. The pressure decreases the size of nanopores and raises their mean spacing. As a result of pressure application, the maximal magnetic induction grows, in contrast to the remanent induction. A correlation between the magnetic properties and nanoporosity of the alloy is discussed.     

Structure of amorphous Fe80-P13-C7 alloy by X-ray diffraction

In the frame of a semiclassical picture a systematic approximation scheme for the hopping-conductivity is derived which provides a classification in terms of the length of correlated hopping-chains. With the aid of an integral equation for the propagation probability of carriers and a decoupling procedure for configuration averages, conductivity is expressed by the zeroth and second moments of independently averaged contributions of paths containing less than a fixed number of hops. A sum rule allows to carry out the static limit explicitly. The lowest order conductivity reduces to a simple form which is presented for later evaluations.     

Phase transition in metallic glasses Fe66Co12Si9B13 and Fe66Ni12Si9b13

Phase transitions were analysed during annealing of amorphous metallic glasses Fe₆₆Co₁₂Si₉B₁₃ and Fe₆₆Ni₁₂Si₉B₁₃. They were measured by means of X-ray diffraction, electrical and Hall resistivity methods. Forming crystalline phases were identified. Those for metallic glasses with cobalt are α-Fe, Fe₃B and Co₂B while those with nickel are α-Fe, Fe₂B, Ni₂B.     

Amorphous FexCo78-xSi9B13 alloys in radio frequency fields

The “rf collapse” effect is used to determine the quadrupole splitting distributions in ferromagnetic amorphous Fe_xCo_78-xSi₉B₁₃ alloys. The rf field induces crystallization of amorphous alloys which, for x<60 at.%, suppress the rf collapse.     

Vickers Microhardness and Hyperfine Magnetic Field Variations of Heat Treated Amorphous Fe78Si9B13 Alloy Ribbons

Amorphous Fe₇₈Si₉B₁₃ alloy ribbons were heat treated between 296 and 763 K, using heating rates between 1 and 4.5 K/min. Whereas one ribbon partially crystallized at T _x = 722 K, the other one partially crystallized at T _x = 763 K. The partially crystallized ribbon at 722 K, heat treated using a triangular form for the heating and cooling rates, was substantially less fragile than the partially crystallized at 763 K where a tooth saw form for the heating and cooling rates was used. Vickers microhardness and hyperfine magnetic field values behaved almost concomitantly between 296 and 673 K. The Mössbauer spectral line widths of the heat-treated ribbons decreased continuously from 296 to 500 K, suggesting stress relief in this temperature range where the Vickers microhardness did not increase. At 523 K the line width decreased further but the microhardness increased substantially. After 523 K the line width behave in an oscillating form as well as the microhardness, indicating other structural changes in addition to the stress relief. Finally, positron lifetime data showed that both inner part and surface of Fe₇₈Si₉B₁₃ alloy ribbons were affected distinctly. Variations on the surface may be the cause of some of the high Vickers microhardness values measured in the amorphous state.     

与Al发生扩散反应的非晶(Fe0.99Mo0.01)78Si9B13晶化

高压下与Ａｌ发生扩散反应的非晶（Ｆｅ０．９９Ｍｏ０．０１）７８Ｓｉ９Ｂ１３（ＦＭＳＢ）的不同。与Ａｌ反应的ＦＭＳＢ非晶在３．０￣５．０ＧＰａ,７８０￣９００Ｋ热处理时,晶化为α－Ｆｅ（Ａｌ）和次亚稳非晶合金;在这一压力范围以外,７２０￣９００Ｋ热处理时,晶化为α－Ｆｅ（Ｓｉ）,Ｆｅ３Ｂ或Ｆｅ２Ｂ。与Ａｌ发生反应的ＦＭＳＢ非晶可能通过与Ａｌ的扩散反应在Ａｌ／ＦＭＳＢ界面开始晶化。压力和温度对晶化过程     

连续超短电脉冲对非晶Fe_(78)Si_9B_(13)合金软磁性能的影响

对非晶Fe78Si9B13合金进行了连续超短脉冲电流处理,测量了处理后试样的综合软磁性能.实验证明,当基体金属相αFe(Si)析出量为3%左右,αFe(Si)颗粒大小约为33nm时,可以获得较好的软磁性能.如最大磁导率提高、矫顽力明显降低.利用随机各向异性模型讨论了连续超短脉冲电流处理改善非晶Fe78Si9B13合金软磁性能的机理     

纳米Cu固体材料的X射线衍射与正电子湮没研究

采用自悬浮-冷压法,在不同压力下制得纳米Cu固体材料并对其在不同温度和保温时间下进行退火,利用X射线衍射(XRD)和正电子湮没寿命谱(PAS)分析对材料的结构和微观缺陷进行了表征。XRD分析表明,压制而得的样品晶粒度为20 nm,低于300 ℃退火3 h后并未发现晶粒显著长大;PAS分析表明,压制后的样品缺陷主要为单空位和空位团,大空隙很少,随着退火温度的升高和退火时间的延长,单空位通过扩散结合成空位团,大空隙也在温度较高时分解为空位团,导致空位团的含量增加,而单空位和大空隙的含量降低。     

纳米Cu固体材料的X射线衍射与正电子湮没研究

 采用自悬浮-冷压法,在不同压力下制得纳米Cu固体材料并对其在不同温度和保温时间下进行退火,利用X射线衍射(XRD)和正电子湮没寿命谱(PAS)分析对材料的结构和微观缺陷进行了表征。XRD分析表明,压制而得的样品晶粒度为20 nm,低于300 ℃退火3 h后并未发现晶粒显著长大;PAS分析表明,压制后的样品缺陷主要为单空位和空位团,大空隙很少,随着退火温度的升高和退火时间的延长,单空位通过扩散结合成空位团,大空隙也在温度较高时分解为空位团,导致空位团的含量增加,而单空位和大空隙的含量降低。