Las propiedades de las aleaciones metálicas dependen de la microestructura y, en particular, de su tamaño de grano. Más aún, al reducirse este tamaño hasta longitudes del orden del nanómetro (materiales nanoestructurados), se alteran las propiedades con respecto a las que presentan las aleaciones convencionales, que tienen tamaños...
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November 27, 2014 (v1)PublicationUploaded on: December 4, 2022
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February 2, 2016 (v1)Publication
In situ high-temperature x ray diffraction and magnetization measurements were performed on a melt-spun (Fe70Ni30)88Zr7B4Cu1 amorphous alloy to follow its structural evolution. At 728 K, a bcc-FeNi phase was observed as the primary crystallization product followed by transformation to an fcc phase rv773 K. During cooling to room temperature,...
Uploaded on: March 27, 2023 -
January 22, 2016 (v1)Publication
Thermal evolution of Fe neighbourhood in a supersaturated bcc Fe(Ge,Nb) solid solution, obtained as the final product of mechanical alloying of Fe75Ge20Nb5, was studied. No changes in Fe neighbourhood were detected after heating up to 473 K, although differential scanning calorimetry shows a clear deviation of the baseline at 400 K. After...
Uploaded on: December 4, 2022 -
June 6, 2023 (v1)Publication
Production of the intermetallic MnCo0.8Fe0.2Ge phase, interesting as magnetocaloric material, is obtained by using an almost fully amorphous mechanically alloyed precursor. Thermal treatment to develop the intermetallic phase has been reduced in time (from several hours or even days to few minutes), and temperature (from 1123 K to 723 K)....
Uploaded on: June 7, 2023 -
December 7, 2016 (v1)Publication
The mechanical alloying process of Fe75Nb10B15 and Fe85Nb5B10 systems has been studied from an initial mixture of elemental powders. The amorphization process is monitored by X-ray diffraction and Mössbauer spectrometry. An amorphous phase is formed after 400 h milling only for Fe75Nb10B15 alloy, whereas a bcc supersatured solid solution is the...
Uploaded on: March 27, 2023 -
June 13, 2023 (v1)Publication
Mechanical alloying, a ball milling technique where heterogeneous starting powders are homogenized and alloyed, has become a versatile technique for the production of metastable microstructures: nanocrystalline and/or amorphous alloys, supersaturated solid solutions, etc. Ball milling is affected by many experimental parameters and the analysis...
Uploaded on: June 15, 2023 -
June 1, 2023 (v1)Publication
A Fe83B10Zr6Cu1 melt-spun amorphous alloy has been ball milled in the presence of partially crystalline ribbon pieces, in order to speed up its mechanical nanocrystallization process. Microstructure and magnetic properties of the resulting powder were studied as a function of the milling time. A continuous increase of the crystalline fraction...
Uploaded on: June 2, 2023 -
January 21, 2016 (v1)Publication
Saturation magnetization and magnetic anisotropy have been studied during mechanical alloying of Fe75Nb10B15 alloys prepared using crystalline and commercial amorphous boron. The evolution of saturation magnetization indicates a more efficient dissolution of boron into the matrix using amorphous boron, particularly for short milling times. The...
Uploaded on: March 27, 2023 -
August 21, 2019 (v1)Publication
Mechanical alloying using a planetary ball mill allowed us to obtain two homogeneous systems formed by units with nanometer size and MnCo0.8Fe0.2Ge1−xSix stoichiometry (x = 0 and 0.5). The phase evolution of the systems with the milling time was analyzed using X-ray diffraction. Thermal stability of the final products was studied using...
Uploaded on: March 27, 2023 -
June 12, 2023 (v1)Publication
Fe-Nb-B alloys prepared by ball milling can undergo a complex microstructural evolution during milling. In order to overcome the limitations imposed by traditional X-ray bulk analysis, a comprehensive multi-technique approach was devised to systematically characterize samples with the required resolution. A combination of in situ FIB (focused...
Uploaded on: June 14, 2023 -
June 2, 2023 (v1)Publication
X-ray diffraction patterns of mechanically alloyed Fe85Nb5B10 powder were fitted using whole powder pattern decomposition procedure to resemble the presence of α-Fe type crystals with different Nb content. To do so, a distribution of lattice parameters was proposed based on the asymmetry of the diffraction maxima and the broadening of the...
Uploaded on: June 3, 2023 -
December 7, 2016 (v1)Publication
Co62Nb6Zr2B30 composition was mechanically alloyed using three different types of boron powders in the starting mixture: crystalline β-B, commercial amorphous B and optimized amorphous B via ball milling. Using optimized amorphous B, amorphization process of the alloy is more efficient but milling to optimize amorphous B introduces some...
Uploaded on: March 27, 2023 -
February 2, 2016 (v1)Publication
The temperature dependent magnetization of nanocomposite alloys has been fit with a modified Handrich-Kobe equation with an asymmetric exchange fluctuation parameter combined with the Arrott-Noakes equation. The two equations of state are combined to calculate the entropy change in the magnetocaloric effect associated with the ferromagnetic to...
Uploaded on: March 27, 2023 -
June 1, 2023 (v1)Publication
Mechanically amorphized MnCo1−xFexGe alloys (x = 0.20, 0.06 and 0.03) were used as precursors to obtain hexagonal austenite single phase samples. Combining thermomagnetic and magnetocaloric analysis and in situ X-ray diffraction, we observed that the presence of a distribution of transition temperatures jeopardizes the first order character of...
Uploaded on: June 2, 2023 -
December 7, 2016 (v1)Publication
Dynamical analysis of the movement of a single ball in a planetary ball mill yields a cubic law with the frequency of the mill for the power released during the process. This fact has been explored for two binary compositions (Fe70Zr30 and Fe70Nb30) using two different milling frequencies. The experimental techniques used, in general, support...
Uploaded on: March 27, 2023 -
December 7, 2016 (v1)Publication
Nanocrystalline alloys of nominal composition Fe85Nb5B10 were produced by mechanical alloying from a mixture of elemental powders. Two commercial boron structures were used: amorphous and crystalline. In addition, a third composition Fe94.4Nb5.6 was prepared for comparison. X-ray diffraction and Mössbauer spectroscopy were used to describe the...
Uploaded on: March 27, 2023 -
January 21, 2016 (v1)Publication
Fe75Nb10B15 amorphous ribbons were grinded via ball milling to produce powder samples preserving the amorphous microstructure. A continuous increase of the Curie temperature with the milling time is observed as well as an enhancement of spontaneous magnetization, average hyperfine field, and magnetocaloric effect. This...
Uploaded on: December 4, 2022 -
December 7, 2016 (v1)Publication
Mechanical alloyed Fe75Nb10B15 systems, prepared with crystalline or commercial amorphous boron and a similar composition with the same Fe/Nb ratio but no boron, have been studied as a function of milling time in the aim of enhancing the homogenization of boron and determining its role on the mechanical alloying process. Neither boron addition...
Uploaded on: March 27, 2023 -
January 25, 2016 (v1)Publication
The magnetocaloric response of mechanically alloyed Fe75Nb10B15 powders was studied for samples with different amorphous and nanocrystal volume fractions. Thermomagnetic properties scale following a 3 law for different milling processes, where is the milling frequency. Curie temperature of the amorphous phase increases as the amorphous...
Uploaded on: December 4, 2022 -
January 29, 2016 (v1)Publication
In recent years, the magnetocaloric effect is studied not only for the search of potential magnetic refrigerant materials but also for the analysis of critical phenomena. In both cases, the demagnetizing field might have a notable influence on the results. In this work, we carry out a systematic study, based on theoretical simulations, of the...
Uploaded on: March 27, 2023 -
February 1, 2016 (v1)Publication
In this work, we propose a method to extract the individual parameters that describe the field dependence of magnetic entropy change of each phase in a multiphase system. This method makes use of the scaling laws of the magnetocaloric effect and can help us to determine the behavior of individual phases and to predict their critical exponents....
Uploaded on: December 4, 2022 -
June 5, 2023 (v1)Publication
The magnetocaloric effect (MCE) has been measured for an amorphous mechanically alloyed (MA) Co62Nb6Zr2B30. It is demonstrated that sample shape must be taken into account for a correct interpretation of the results, especially to correctly determine the field dependence of magnetic entropy change and refrigerant capacity. However, although...
Uploaded on: June 7, 2023 -
December 7, 2016 (v1)Publication
Determining the composition at the nanoscale generally requires the use of experimental techniques such as 3D atom probe or nanoanalysis, which have limited availability, involve high economic cost and, moreover, imply aggressive sample preparations. However, the combination of Mössbauer spectrometry (MS), X-ray diffraction (XRD) and...
Uploaded on: March 27, 2023 -
June 13, 2023 (v1)Publication
The milling time evolution of magnetic anisotropy of ball milled powders can be described considering two regimes. First, for short milling times, the main factor affecting the magnetic behavior of the alloy is the accumulation of internal stresses. Second, for long milling times, magnetic anisotropy can be explained using three contributions:...
Uploaded on: June 15, 2023