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Formation of ferromagnetic bulk amorphous Fe40Ni40P14B6 alloys  [PDF]
Qiang Li
Physics , 2006, DOI: 10.1016/j.matlet.2006.02.054
Abstract: Ferromagnetic bulk amorphous Fe40Ni40P14B6 alloy rods with a diameter of 1.2 mm can be prepared by means of a rapid quenching technique. If a fluxing technique is also used, amorphous rods with a diameter as large as 2.5 mm can be synthesized. The critical cooling rate Rc for the glass formation Fe40Ni40P14B6 is estimated to be on the order of 100 K.s-1


材料研究学报 , 1997,
Abstract: A hot high-pressure compaction of melt--spun amorphous metallic ribbons which produces fully-densed bulk amorphous samples, was developed by using an amorphous Ni69Cr7Fe2.5Si8B13.5 alloy ribbons as a model material. Under a pressure of 1.5GPa, the crystallization onset temperature was found to be increased by about 40K, resulting in a widened supercooled liquid temperature region of about 60K beneath the onset of crystallization. Consolidation of the amorphous ribbons in temperatures of 733~ 773 K with a pressure higher than 1.5GPa yielded bulk amorphous compacts with full density (>99% of the theoretical value). This achievement was attributed to the significant homogenous viscous flow of materials in the supercooled liquid state.
Superconducting State Parameters of Bulk Amorphous Alloys  [PDF]
Aditya M.?Vora
Journal of Nano- and Electronic Physics , 2012,
Abstract: Well recognized empty core (EMC) pseudopotential of Ashcroft is used to investigate the superconducting state parameters viz; electron-phonon coupling strength λ, Coulomb pseudopotential μ*, transition temperature TC, isotope effect exponent α and effective interaction strength NOV of some (Ni33Zr67)1 – xVx (x = 0, 0.05, 0.1, 0.15) bulk amorphous alloys. We have incorporated five different types of local field correction functions, proposed by Hartree (H), Taylor (T), Ichimaru-Utsumi (IU), Farid et al. (F) and Sarkar et al. (S) to show the effect of exchange and correlation on the aforesaid properties. Very strong influence of the various exchange and correlation functions is concluded from the present study. The TC obtained from Sarkar et al. (S) local field correction function are found an excellent agreement with available theoretical data. Quadratic TC equation has been proposed, which provide successfully the TC values of bulk amorphous alloys under consideration. Also, the present results are found in qualitative agreement with other such earlier reported data, which confirms the superconducting phase in the s bulk amorphous alloys.
Iron - based bulk amorphous alloys  [PDF]
R. Babilas,R. Nowosielski
Archives of Materials Science and Engineering , 2010,
Abstract: Purpose: The paper presents a structure characterization, thermal and soft magnetic properties analysis of Fe-based bulk amorphous materials in as-cast state and after crystallization process. In addition, the paper gives some brief review about achieving, formation and structure of bulk metallic glasses as a special group of amorphous materials.Design/methodology/approach: The studies were performed on Fe72B20Si4Nb4 metallic glass in form of ribbons and rods. The amorphous structure of tested samples was examined by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) methods. The thermal properties of the glassy samples were measured using differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The magnetic properties contained initial and maximum magnetic permeability, coercive force and magnetic after-effects measurements were determined by the Maxwell-Wien bridge and VSM methods.Findings: The X-ray diffraction and transmission electron microscopy investigations revealed that the studied as-cast bulk metallic glasses in form of ribbons and rods were amorphous. Two stage crystallization process was observed for studied bulk amorphous alloy. The differences of crystallization temperature between ribbons and rods with chosen thickness are probably caused by different amorphous structures as a result of the different cooling rates in casting process. The SEM images showed that studied fractures could be classified as mixed fractures with indicated two zones contained “river” and “smooth” areas. The changing of chosen soft magnetic properties (μr, Bs, Hc) obtained for samples with different thickness is a result of the non-homogenous amorphous structure of tested metallic glasses. The annealing process in temperature range from 373 to 773 K causes structural relaxation of tested amorphous materials, which leads to changes in their physical properties. The qualitative phase analysis from X-ray and TEM diffraction data enables the identification of a single phase of α-Fe for sample annealed at 823 K and a mixture of Fe2B, Fe3B and Fe23B6 and α-Fe phases for samples annealed at temperature of 873 and 923 K.Practical implications: The magnetic properties allow to classify the studied Fe-based glassy alloy for suitable material for electric and magnetic applications. These properties of could be improved by applying the appropriate conditions of heat treatment (crystallization process).Originality/value: The applied investigation methods are suitable to determine the changes of structu
Survey of BGFA Criteria for the Cu-Based Bulk Amorphous Alloys
D. Janovszky,K. Tomolya,M. Sveda,A. Roosz
Journal of Metallurgy , 2011, DOI: 10.1155/2011/895146
Abstract: To verify the effect of composition on the bulk glass forming ability (BGFA) of Cu-based alloys, properties have been collected from the literature (~100 papers, more than 200 alloys). Surveying the BGFA criteria published so far, it has been found that the atomic mismatch condition of Egami-Waseda is fulfilled for all the Cu-based BGFAs, the value being above 0,3. The Zhang Bangwei criterion could be applied for the binary Cu-based alloys. The Miracle and Senkov criteria do not necessarily apply for Cu based bulk amorphous alloys. The critical thickness versus =/(
Formation of bulk ferromagnetic nanostructured Fe40Ni40P14B6 alloys by metastable liquid spinodal decomposition  [PDF]
Qiang Li
Physics , 2007,
Abstract: Nanostructured Fe40Ni40P14B6 alloys ingots of diameter 3~5 mm could be synthesised by a metastable liquid state spinodal decomposition method. The molten Fe40Ni40P14B6 alloy was purified by means of the fluxing technique and thus a large undercooling could be achieved. For undercooling Delta T > 260 K, the microstructure of the undercooled specimen had exhibited liquid state spinodal decomposition in the undercooled liquid state. The microstructure could be described as two intertwining networks with small grains dispersed in them. For undercooling Delta T > 290 K, the overall microstructure of the specimen changed into a granular morphology. The average grain sizes of the small and large grains are ~ 30 nm and ~ 80 nm, respectively. These prepared samples are soft magnets with saturation magnetization Bs ~0.744 T.
Critical cooling rate for the glass formation of ferromagnetic Fe40Ni40P14B6 alloy  [PDF]
Qiang Li
Physics , 2006,
Abstract: Bulk ferromagnetic amorphous Fe-Ni-P-B alloys in rod shape were formed by a rapid solidification technique. The largest amorphous specimen prepared had a diameter of ~2.5 mm and the corresponding cooling rate for the glass formation of this alloy system in our experiment can be estimate to be around 492.4 K/s by the method of finite-difference numerical calculation. This value is on the same order of magnitude as the critical cooling rate Rc of Fe40Ni40P14B6 alloy estimated by the method of constructing the continuous-cooling-transformation (CCT) curve. It is indicated that the heterophase impurities have been eliminated well in our experiment.
Surface and bulk properties of thick amorphous iron alloys  [PDF]
Marcin Nabialek,Katarzyna Sobczyk,Joanna Gondro,Monika Gwozdzik
Optica Applicata , 2009,
Abstract: The microstructure and mechanical properties, such as hardness and abrasive resistance, for the amorphous Fe60Co5Zr8Mo5W2B20 samples in the form of plate and rod have been investigated. We have stated that the samples obtained by a suction-casting method were fully amorphous. Moreover, from M ssbauer spectroscopy studies we have found that the amorphous rod is more homogenous than the plate. It is due to different quenching rates in the layers located near the surface and inside the samples. Hardness on the side surface of the plate or rod are almost the same in different measured points. However, hardness in the cross-section of the rod exhibits the maximum value near its surface. It is worth noticing that hardness of the amorphous samples is about twofold larger than for crystalline ingots. Wear resistance of the outer layer is smaller than for layers located near the centre of the sample.
High-strength Zr-based bulk amorphous alloys containing nanocrystalline and nanoquasicrystalline particles
A Inoue, C Fan, J Saida and T Zhang
Science and Technology of Advanced Materials , 2000,
Abstract: It was recently found that the addition of special elements leading to the deviation from the three empirical rules for the achievement of high glass-forming ability causes new mixed structures consisting of the amorphous phase containing nanoscale compound or quasicrystal particles in Zr–Al–Ni–Cu–M (M=Ag, Pd, Au, Pt or Nb) bulk alloys prepared by the copper mold casting and squeeze casting methods. In addition, the mechanical strength and ductility of the nonequilibrium phase bulk alloys are significantly improved by the formation of the nanostructures as compared with the corresponding amorphous single phase alloys. The composition ranges, formation factors, preparation processes, unique microstructures and improved mechanical properties of the nanocrystalline and nanoquasicrystalline Zr-based bulk alloys are reviewed on the basis of our recent results reported over the last two years. The success of synthesizing the novel nonequilibrium, high-strength bulk alloys with good mechanical properties is significant for the future progress of basic science and engineering.
Research Advances in Bulk Amorphous Alloys

卢静, 严淑群, 罗丰华, 夏光明, 闵小兵
Material Sciences (MS) , 2016, DOI: 10.12677/MS.2016.64031
Bulk amorphous alloys (bulk metallic glasses) are widely researched for its unique microstructure and excellent Properties. This paper summarizes the research progress in domestic and overseas, the development system and components design of bulk amorphous alloy, and focuses on the preparation method of the alloy, excellent product performance and its application, then, the ap-plication of bulk amorphous alloy in more fields is expected.
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