An equivalent time approach for scaling the mechanical alloying processes

Ipus, J.J.; Blázquez, J.S.; Franco, V.; Millán, M.; Conde, A.; Oleszak, D.; Kulik, T.

doi:10.1016/j.intermet.2007.12.011

Cited by 23 publications

(29 citation statements)

References 28 publications

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“…This process was done six times and, in the following, they will be named as milling steps from 1 to 6 (4,8,12,16,20 and 24 h milling at 360 rpm and 8, 16, 24, 32, 40…”

Section: Methodsmentioning

confidence: 99%

“…Several attempts have been done to estimate the energy release during ball milling processes [2,3]. Recently, it has been shown that the power released during milling is proportional to the cubic power of the rotational frequency in planetary ball mills [4]. This leads to a definition of an equivalent milling time t eq =t·(/ 0 ) 3 , where t is the milling time,  is the rotational frequency of the mill and  0 is a reference frequency.…”

Section: Introductionmentioning

confidence: 99%

“…This leads to a definition of an equivalent milling time t eq =t·(/ 0 ) 3 , where t is the milling time,  is the rotational frequency of the mill and  0 is a reference frequency. This model has been successfully applied to compare the evolution of different properties of powder obtained at different milling intensities [4,5].…”

Section: Introductionmentioning

confidence: 99%

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Comparison of equivalent ball milling processes on Fe70Zr30 and Fe70Nb30

Blázquez¹,

Ipus²,

Conde³

et al. 2012

Journal of Alloys and Compounds

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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: Fe 70 Zr 30 and Fe 70 Nb 30 using two different milling frequencies. The experimental techniques used, in general, support the predictions of the equivalent milling time model. However, some deviations appear which could be ascribed to differences in the temperature inside the vial during milling. Journal of Alloys and Compounds, 536S1 (2012) and approximately the same amount of sample ~0.2 g was extracted in argon atmosphere for each composition. This process was done six times and, in the following, they will be named as milling steps from 1 to 6 (4, 8, 12, 16, 20 and 24 h milling at 360 rpm and 8, 16, 24, 32, 40 and 48 h milling at 286 rpm, respectively). At the first milling step no powder could be recover for the Zr alloy but the starting material stuck on the ball and vial surfaces forming a shiny layer.Samples were analyzed using differential scanning calorimetry (DSC) in a PerkinElmer DSC7; X-ray diffraction (XRD) using Cu-K wavelength, scanning electron microscopy (SEM) in a Jeol JSM-6460 LV and Mössbauer spectrometry (MS) in a transmission geometry using a 57 Co(Rh) source. Values of the hyperfine parameters were obtained by fitting with NORMOS program [6]. The isomer shift, IS, was quoted relative to the Mössbauer spectrum of an -Fe foil at room temperature. 3Results and discussion Figure 1 shows the XRD patterns of several samples. The amorphous phase of the asmilled samples is evidenced by a broad amorphous halo. Figure 2 shows the DSC scans at 40 K/min of the different studied samples. All the features observed in the curves are irreversible as they disappear in a second scan, which was used as the corresponding baseline. A general agreement can be found for the two samples of each composition obtained at the same milling step. This is especially clear concerning the broad exothermic peak ascribed to the release of the energy stored during milling (structural and strain relaxation phenomena at low temperatures and grain growth and crystallization phenomena at high temperatures). For allJournal of Alloys and Compounds, 536S1 (2012) 9-12 http://dx.doi.org/10.1016/j.jallcom.2011.11.084 the samples, a deviation from the baseline occurs about 400 K which coincides with a slight decrease of the mass of the sample observed by thermomagnetic gravimetry, TG (both experiments, DSC and TG were performed under argon flow). Thus this feature should be ascribed to some gas desorption from the powders.However, concerning endothermic processes some differences arise between the two set of experiments performed at different frequencies and depending on the studied composition. For Nb alloy, there is an endothermic peak about 625 K which appears only for the samples milled at 360 rpm. Similar endothermic peaks were found in FeGeNb powders being ascribed to solving intermetallic(...

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“…This process was done six times and, in the following, they will be named as milling steps from 1 to 6 (4,8,12,16,20 and 24 h milling at 360 rpm and 8, 16, 24, 32, 40…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Comparison of equivalent ball milling processes on Fe70Zr30 and Fe70Nb30

Blázquez¹,

Ipus²,

Conde³

et al. 2012

Journal of Alloys and Compounds

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“…In the case of a-B alloy we can see the formation of some amorphous fraction, even after 3 h milling, while for c-B alloy the amorphous phase is only detected by XRD after 6 h milling. As the milling conditions were the same for both alloys, this difference in time evidences that the c-B alloy needs approximately double energy (dose) transferred to the powders from the milling media [16,17] to produce a similar microstructure. The rate at which the crystalline fraction decreases is higher for a-B alloy up to 10 h, which means a faster developing of amorphous phase for this alloy.…”

Section: Discussionmentioning

confidence: 90%

Role of starting phase of boron on the mechanical alloying of FeNbB composition

Ipus

Blázquez

Franco

et al. 2013

Journal of Alloys and Compounds

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Mechanical alloyed Fe 75 Nb 10 B 15 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 nor boron phase used affect the developed microstructure at very early stages. After 4 h milling at 350 rpm, the formation of an amorphous phase was observed for boron containing compositions while for the boron-free alloy a supersaturated solid solution was found in the final microstructure. The alloy prepared using commercial amorphous boron showed a larger fraction of amorphous phase than that prepared using crystalline boron for the same milling time, suggesting that amorphous boron accelerates the formation of the amorphous phase during mechanical alloying.

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“…Previous studies [5] show that the power released during milling scales with the cube of the frequency of the main disk, U, in a planetary mill. This law has been tested for the microstructural and magnetic properties evolution of Fe-Ge-Nb alloys [5] and for magnetization, Curie temperature and magnetocaloric effect of Fe-Nb-B alloys from vibrating sample magnetometry [6].…”

Section: Introductionmentioning

confidence: 99%