Analysis of the Samples of Fe-Cu-Nb-Si-B Amorphous Alloys Obtained by Dynamic Compacting Method

2005 ◽  
Vol 903 ◽  
Author(s):  
Victor A. Golubev ◽  
Andrey V. Strikanov ◽  
Grigory A. Potemkin ◽  
Ludmila V. Zueva ◽  
Aleksey V. Golubev ◽  
...  

AbstractThe Dynamic Compacting (DC) method is promising method to produce considerable-size nonporous wares. The phenomenon is based on the impact of shock wave on the initial powders of amorphous alloys. Every time when the shock wave propagates through the bulk of substance then the temperature rises substantially. Therefore there is a need of study of the DC’s effect on the structure and properties of the amorphous alloys. The results of the thermal analysis (in particular, Differential Scanning Calorimetry) of the samples of the soft magnetic alloys are presented in the report. These results concern with amorphous alloys of 5BDSR, GM414, 10NSR trademarks before DC and after DC, respectively. It is shown there is single low-temperature endothermic peak (near 300C) and there are several high temperature exothermic peaks (near 540C, 650C, and 700C). The first peak is related to glass-transition, the following peaks are related to formation of nano-crystalline phases. It was proved by XRD analysis data. The optimal regimes of the thermal processing of final wares were chosen on the base of thermal- and XRD-analysis. The study of the effects of these regimes on the properties (magnetic conductivity, specific losses etc.) of the circular magnetic conductors was executed. In particular, thermal- as well as thermo-magnetic processing of magnetic conductors based on 5BDSR amorphous alloy (after DC) essentially improves their magnetic properties. For example, magnetic conductivity fÝ increases approximately by factor 17 with respect to the magnitude before DC.

2005 ◽  
Vol 903 ◽  
Author(s):  
Victor A. Golubev ◽  
Andrey V. Strikanov ◽  
Aleksey V. Golubev ◽  
Vladimir G. Bugrov ◽  
Grigory A. Potemkin ◽  
...  

AbstractAt present amorphous metallic alloys have the broad expansion in various fields of science&engineering as a result of their unique properties. In particular, soft magnetic amorphous alloys are extensively used in electrical engineering. However the production of considerable-size nonporous wares based on the powders (or tapes) of these alloys is heavy problem owing to high hardness of the particles. Therefore shock wave’s compacting or Dynamic Compacting (DC) method is promising one to produce the wares on the base of powders of amorphous alloys because it can provides high strength and near zero porosity of the wares. The experimental D-U diagrams of soft magnetic amorphous alloys were obtained to realize this method of compacting. The calculations of the amplitude and duration of shock wave were carried out. The several versions of explosive devices using shock plane wave generator to produce circular magnetic conductors were developed and were tested. These magnetic conductors are based on amorphous alloys of 5BDSR, GM414, 10NSR trademarks (Fe with Cu, Nb, Si, B additives). XRD analysis proved that amorphous state of the alloys remains the same up to 20 GPa shock wave’s pressures. The mechanical, structural, electrical and magnetic properties both initial amorphous alloys and compacted one were obtained and compared as a result of the implemented works. It was stated that DC leads to increase of magnetic conductivity by factor ∼15 with respect to initial amorphous alloys powder. Besides the specific losses decrease in ∼4 times.


2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Conghua Hou ◽  
Xinlei Jia ◽  
Jingyu Wang ◽  
Yingxin Tan ◽  
Yuanping Zhang ◽  
...  

A new one-step granulation process for preparing high melting explosive- (HMX-) based PBX was developed. HMX/F2602 microspheres were successfully prepared by using HMX and F2602 as the main explosive and binder, respectively. The particle morphology, particle size, crystal structure, thermal stability, and impact sensitivity of the as-prepared HMX/F2602 microspheres were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), laser particle size analyzer, differential scanning calorimetry (DSC), and impact sensitivity test, respectively. The SEM analysis indicated successful coating of F2602 on the surface of HMX, and the resulting particles are ellipsoidal or spherical with a median particle size of 940 nm; the XRD analysis did not show any change in the crystal structure after the coating and still has β-HNX crystal structure; according to the DSC analysis, HMX/F2602 prepared by the new method has better thermal stability compared to that prepared by the water suspension process. The impact sensitivity of HMX/F2602 prepared by this one-step granulation process decreased, and its characteristic height H50 increased from 37.62 to 40.13 cm, thus significantly improving the safety performance. More importantly, this method does not need the freeze-drying process after recrystallization, thus increasing the efficiency by 2 to 3 times.


2016 ◽  
Vol 51 (18) ◽  
pp. 2665-2673 ◽  
Author(s):  
Behzad Kord ◽  
Mehdi Roohani

The physical, mechanical, thermal, and flammability properties of high-density polyethylene/old corrugated container composites reinforced with carbon nanotubes are presented in this study. High-density polyethylene/old corrugated container composites with different loadings of carbon nanotube (0, 1, 3, and 5 phc) were prepared by melt compounding followed by injection molding. Results indicated that the incorporation of carbon nanotube into high-density polyethylene, significantly improved the mechanical properties of the composites. The tensile and flexural properties achieved the maximum values when 3 phc carbon nanotube was added. Meanwhile, the impact strength of the composites progressively decreased with increasing carbon nanotube content. Furthermore, the water absorption and thickness swelling of the samples remarkably reduced with the addition of carbon nanotube. From thermogravimetric analysis data, the presence of carbon nanotube could enhance the thermal stability of the composites, especially the maximum weight loss rate temperature and also the better char residual was obtained at high loading level of carbon nanotube. Simultaneous differential scanning calorimetry thermograms revealed that the thermal degradation temperatures for the samples with carbon nanotube were much higher than those made without carbon nanotube. Moreover, it was found that the addition of carbon nanotube results in a significant enhancement in flame retardancy of the composites. Morphological observations showed that the nanoparticles were predominantly dispersed uniformly within the high-density polyethylene matrix.


2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940006
Author(s):  
Xiang Li ◽  
Xu Zhao ◽  
Fang Liu ◽  
Lu Yu ◽  
Yuxin Wang

Fe-based amorphous alloys are important materials with a high potential for commercialization by evaluating their corrosion performances. In this work, amorphous Fe[Formula: see text]Cu1Nb3Si[Formula: see text]B9 alloy was chosen as a target material to investigate the effects of the addition of C on the corrosion properties by an electrochemical method. Alloy ingots Fe[Formula: see text]Cu1Nb3Si[Formula: see text]C[Formula: see text]B[Formula: see text] (x = 0, 1, 2, 3 at.%) were prepared using an arc melting system, under argon atmosphere. Planar flow melt spinning of the alloys was carried out to obtain amorphous ribbons of the width [Formula: see text][Formula: see text]5 mm and the thickness about 30 [Formula: see text]m. Effects of the addition of C into Fe[Formula: see text]Cu1Nb3Si[Formula: see text]B9 amorphous soft magnetic alloys were investigated in acidic solutions. Studies of potentiodynamic polarization and electrochemical impedance revealed the passivation ability and corrosion resistance of the amorphous ribbons with C in the 0.1M H2SO4 media at room-temperature. The amorphous ribbons showed excellent corrosion resistance with formation of a stable passive film. It can be obviously observed that the addition of C significantly improves the corrosion resistance.


2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Conghua Hou ◽  
Congcong Li ◽  
Xinlei Jia ◽  
Yuanping Zhang ◽  
Shimin Zhang

To improve the safety of ammonium nitrate explosives, a one-step method involving the formation of CL-20/TATB/VitonA composite microspheres using spray drying is presented. The crystal morphology, particle size, crystal structure, thermal properties, and sensitivity of raw materials of CL-20 and TATB, CL-20/VitonA particles, and CL-20/TATB/VitonA microspheres were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and impact and friction sensitivity tests. The SEM results show that the prepared CL-20/TATB/VitonA composites with micro-/nanoscale grain size have a good spherical shape. Thermal analysis data show that TATB coating enhances the thermal stability of CL-20/VitonA. The impact and friction sensitivity results show that superior mechanical properties of these composite microspheres could be maintained. Obviously, this approach is an effective desensitization technique to prepare composite microspheres for explosives.


2005 ◽  
Vol 475-479 ◽  
pp. 3393-3396
Author(s):  
Hui Xu ◽  
Xiao Hua Tan ◽  
Nannan Qi ◽  
Qing Wang ◽  
Yuanda Dong

The glass-forming ability, thermal stability and magnetic properties of the Nd60-xDyxFe30Al10 (x=0, 2, 5) bulk amorphous alloys were investigated by x-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscope (SEM) and the vibrating sample magnetometer (VSM). The results show that the glass forming ability of the Nd60-xDyxFe30Al10 (x=0, 2, 5) alloys decrease with increasing Dy content. The as-cast Nd60-xDyxFe30Al10 (x=0, 2, 5) alloys show hard magnetic behavior at room temperature. With increasing Dy content, the intrinsic coercivity of the alloys increase significantly while the saturation magnetization and remanence of the alloys decrease monotonously. With increasing annealed temperature, the intrinsic coercivity of the Nd55Fe30Al10Dy5 alloy decreased significantly, while the saturation magnetization and remanence decrease monotonously. The Nd55Fe30Al10Dy5 alloy shows soft magnetic behavior after annealed at 773K for 30 min.


Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 304
Author(s):  
Jonghee Han ◽  
Jihyun Hong ◽  
Seoyeon Kwon ◽  
Haein Choi-Yim

In the Fe-Co alloy system, the addition of Cr improves the glass-forming ability (GFA) with superior soft magnetic properties such as high saturation magnetization (Ms) and low coercivity (Hc). In addition, Cr is considered to be an important factor for improving the corrosion resistance of Fe-based amorphous alloy. Therefore, in the present study, we investigated the GFA, soft magnetic properties, and corrosion resistance of the as-spun ribbons in [Co0.075Fe0.675B0.2Si0.05]100−xCrx (x = 0–8) alloy system. The ribbons were produced using the melt-spinning technique and were characterized by X-ray diffraction, differential scanning calorimetry, thermomechanical analysis, and vibrating sample magnetometer. The Co-Fe-B-Si-Cr alloys exhibited high thermal stability and a high Ms of 0.93–1.53 T. Corrosion properties were evaluated by cyclic voltammetry. The addition of Cr improved the corrosion resistance of the alloys. The alloys with a higher Cr content exhibited a higher corrosion resistance. The optimum combination with soft magnetic properties and corrosion resistance of Fe-co based amorphous alloys can be utilized for extensive fields of application through a variation of Cr contents.


2008 ◽  
Vol 570 ◽  
pp. 109-113
Author(s):  
T. Lilly Shanker Rao ◽  
Kirit N. Lad ◽  
Heena Dhurandhar ◽  
Arun Pratap ◽  
Prafulla K. Jha

Soft magnetic alloys consisting of nanoscale fcc Fe grains have been developed by primary crystallization of melt-spun amorphous alloys as typically exemplified in Fe-B[1], Fe-M-B (M = Zr, Hf, Nb) (Nanoperm) [2] and Fe-Si-B-Nb-Cu (FINEMET)systems[3]. Lot of scientific effort has been put in last years to control the crystallization process of metallic glasses. This is due to the fact that several attractive properties of the resulting material are strongly related to the final attained microstructure. In the present paper, primary nanocrystallization kinetics of a Fe–based multicomponent amorphous system namely Fe67Co18B14Si1 (2605CO) has been analysed by nonisothermal DSC measurements. Crystallization is a combined process of nucleation and growth. The amorphous alloy undergoes two-step crystallization with primary crystallization of α-Fe giving the first step. The Avrami exponent for the two steps has been derived. A detailed analysis of the data provides an insight in to the dimensionality and mechanism of growth.


2016 ◽  
Vol 849 ◽  
pp. 85-90
Author(s):  
Jia Chang Gu ◽  
Xiao Tao Han ◽  
Qi Chen

The electrical resistivity of three kinds of Zr-based bulk amorphous alloys as a function of continuous increasing temperature was measured by the direct current four-probe method. Combining with Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis, the correlation between the electrical resistivity and structural evolution of these amorphous alloys has been demonstrated. The experimental results showed that three amorphous alloys all had a small negative temperature coefficient of resistivity (TCR<-10-4 K-1) before crystallization. Little change of the electrical resistivity related with the glass transition process was observed, while the electrical resistivity decreased sharply once the crystallization occurred. The onset of crystallization determined by the electrical resistivity measurement was far lower than that by DSC. The different stages of crystallization behavior could be evidently identified by the change of the electrical resistivity.


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