scholarly journals Seismic fault weakening via CO2 pressurization enhanced by mechanical deformation of dolomite fault gouges

Geology ◽  
2021 ◽  
Author(s):  
Hyun Na Kim ◽  
Byung-Dal So ◽  
Min Sik Kim ◽  
Kee Sung Han ◽  
Sol Bi Oh
Keyword(s):  
Carbon Dioxide Emissions ◽  
Fault Plane ◽  
High Energy ◽  
X Ray Diffraction ◽  
Effective Normal Stress ◽  
Seismic Fault ◽  
High Energy Ball Mill ◽  
Crystalline Dolomite ◽  
Fault Gouges ◽  
Low Crystalline

Carbon dioxide emissions from dolomite decarbonation play an essential role in the weakening of carbonate faults by lowering the effective normal stress, which is thermally activated at temperatures above 600–700 °C. However, the mechanochemical effect of low-crystalline ultrafine fault gouge on the decarbonation and slip behavior of dolomite-bearing faults remains unclear. In this study, we obtained a series of artificial dolomite fault gouges with systematically varying particle sizes and dolomite crystallinities using a high-energy ball mill. The laboratory-scale pulverization of dolomite yielded MgO at temperatures below 50 °C, indicating that mechanical decarbonation without significant heating occurred due to the collapse of the crystalline structure, as revealed by X-ray diffraction and solid-state nuclear magnetic resonance results. Furthermore, the onset temperature of thermal decarbonation decreased to ~400 °C. Numerical modeling reproduced this two-stage decarbonation, where the pore pressure increased due to low-temperature thermal decarbonation, leading to slip weakening on the fault plane even at 400–500 °C; i.e., 200–300 °C lower than previously reported temperatures. Thus, the presence of small amounts of low-crystalline dolomite in a fault plane may lead to a severely reduced shear strength due to thermal decomposition at ~400 °C with a small slip weakening distance.

scholarly journals Influence of prolonged sintering time on density and electrical properties of isothermally sintered cordierite-based ceramics

2013 ◽  
Vol 45 (2) ◽  
pp. 157-164 ◽  
Author(s):  
A. Peles ◽  
N. Djordjevic ◽  
N. Obradovic ◽  
N. Tadic ◽  
V.B. Pavlovic
Keyword(s):  
Electrical Properties ◽  
Mechanical Activation ◽  
Compaction Pressure ◽  
High Energy ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Air Atmosphere ◽  
Atomic Force ◽  
Sintering Time ◽  
High Energy Ball Mill

Mechanical activation is a commonly used and relatively fast and inexpensive procedure for sample preparation before the sintering process. Cordierite, a stoichiometric mixture of three different oxides (2MgO?2Al2O3?5SiO2) is a very attractive, widely used high-temperature ceramic material. The mechanical activation of the starting mixtures with 5.00 mass% TiO2 was performed in a high energy ball mill during 10-80 min. The applied compaction pressure before the sintering process was 2t/cm2, based on our recent investigation. The sintering process was performed at 1350oC for 2h and 4h in air atmosphere. X-ray diffraction was used to analyze the phase composition of non-activated and 80 min activated samples, sintered for 2 and 4h, respectively. Scanning electron microscopy was performed to analyze the microstructure of both compacted and sintered samples. Atomic force microscope was used to investigate the surface of the sintered samples. This paper investigates the influence of prolonged sintering time on the densities of the sintered samples, along with electrical properties.

SYNTHESIS OF NANO-CRYSTALLINE Cu-Cr ALLOY BY MECHANICAL ALLOYING

2012 ◽  
Vol 05 ◽  
pp. 496-501 ◽  
Author(s):  
S. SHEIBANI ◽  
S. HESHMATI-MANESH ◽  
A. ATAIE
Keyword(s):  
Mechanical Alloying ◽  
Structural Evolution ◽  
High Energy ◽  
Lattice Parameter ◽  
Control Agent ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Nano Crystalline ◽  
High Energy Ball Mill ◽  
Energy Ball

In this paper, the influence of toluene as the process control agent (PCA) and pre-milling on the extension of solid solubility of 7 wt.% Cr in Cu by mechanical alloying in a high energy ball mill was investigated. The structural evolution and microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, respectively. The solid solution formation at different conditions was analyzed by copper lattice parameter change during the milling process. It was found that both the presence of PCA and pre-milling of Cr powder lead to faster dissolution of Cr . The mean crystallite size was also calculated and showed to be about 10 nm after 80 hours of milling.

scholarly journals Characterization of Mechanically Alloyed Nanocrystalline Fe(Al): Crystallite Size and Dislocation Density

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
M. Mhadhbi ◽  
M. Khitouni ◽  
L. Escoda ◽  
J. J. Suñol ◽  
M. Dammak
Keyword(s):  
Solid Solution ◽  
Dislocation Density ◽  
Crystallite Size ◽  
Average Crystallite Size ◽  
High Energy ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Scanning Calorimetry ◽  
High Energy Ball Mill

A nanostructured disordered Fe(Al) solid solution was obtained from elemental powders of Fe and Al using a high-energy ball mill. The transformations occurring in the material during milling were studied with the use of X-ray diffraction. In addition lattice microstrain, average crystallite size, dislocation density, and the lattice parameter were determined. Scanning electron microscopy (SEM) was employed to examine the morphology of the samples as a function of milling times. Thermal behaviour of the milled powders was examined by differential scanning calorimetry (DSC). The results, as well as dissimilarity between calorimetric curves of the powders after 2 and 20 h of milling, indicated the formation of a nanostructured Fe(Al) solid solution.

Atmosphere effects of the amorphization reaction in NiZr by ball milling

1993 ◽  
Vol 8 (2) ◽  
pp. 307-313 ◽  
Author(s):  
K. Aoki ◽  
A. Memezawa ◽  
T. Masumoto
Keyword(s):  
High Energy ◽  
Hydrogen Atmosphere ◽  
Nitrogen Atmosphere ◽  
Gas Absorption ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
High Energy Ball Mill ◽  
Energy Ball

An intermetallic compound c–NiZr and a mixture of elemental powders of nickel and zirconium [Ni50Zr50 (at. %)] have been mechanically ground (MG) and mechanically alloyed (MA), respectively, using a high-energy ball mill in various atmospheres. The products were characterized by x-ray diffraction, transmission electron microscopy, differential scanning calorimetry, and chemical analysis as a function of milling time. An amorphous a–NiZr alloy was prepared by both MG and MA in an argon atmosphere. By MG of NiZr, an amorphous nitride a–NiZrN0.15 was synthesized in a nitrogen atmosphere, while a crystalline hydride c–NiZrH3 was formed in a hydrogen atmosphere. On the other hand, ZrN and ZrH2 were formed by MA in a nitrogen and a hydrogen atmosphere, respectively. The amorphization reaction was observed between ZrH2 and Ni by further MA in a hydrogen atmosphere, and a mixture of a–NiZrxHy (x < 1) and ZrH2 was obtained. However, no amorphization was observed by MA between ZrN and Ni in a nitrogen atmosphere. The effects of the milling atmosphere on the phase formations during MG and MA are discussed based on the gas absorption rate.

scholarly journals Synthesis of the Fe-6.5% wt. Si Alloy by Mechanical Alloying

2015 ◽  
Vol 13 ◽  
pp. 109-113 ◽  
Author(s):  
Cristina Daniela Stanciu ◽  
Florin Popa ◽  
Ionel Chicinaş ◽  
Olivier Isnard
Keyword(s):  
Mechanical Alloying ◽  
High Energy ◽  
Alloy Formation ◽  
X Ray Diffraction ◽  
Nanocrystalline State ◽  
Compound Formation ◽  
Dsc Studies ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
Si Content

Fe-Si alloy with a large Si content of 6.5 wt. % is obtained in nanocrystalline state by mechanical alloying of elemental iron and silicon powders. The mechanical alloying process was carried out using a high energy ball mill in argon atmosphere. Samples were collected after 0.5, 1, 2, 4, 6 and 8 hours of ball milling. The X-ray diffraction (XRD) studies indicate that after 4 hours of milling the Fe-Si alloy is formed. The powder magnetisation decreases upon increasing the milling time up to 4 hours as a consequence of the Fe-Si alloy formation. Upon heating, the DSC studies show the Fe3Si compound formation in the samples milled for milling times lower than 6 hours. Also, the Curie temperature of the alloy was evidenced.

Nanocrystalline/Nanosized Mixed Nickel-Manganese Ferrites Obtained by Mechanical Milling

2014 ◽  
Vol 216 ◽  
pp. 243-248
Author(s):  
Ionel Chicinaş ◽  
Traian Florin Marinca ◽  
Bogdan Viorel Neamţu ◽  
Florin Popa ◽  
Olivier Isnard
Keyword(s):  
Mechanical Milling ◽  
High Energy ◽  
Size Analysis ◽  
X Ray Diffraction ◽  
High Energy Ball Mill ◽  
Nanometric Range ◽  
Energy Ball ◽  
The Mean ◽  
Ceramic Route ◽  
Nickel Manganese

A sum of mixed nickel-manganese ferrites, NixMn1-xFe2O4(x=0, 0.3, 0.5, 0.7) were synthesized by classical ceramic route starting from stoichiometric mixtures of commercially MnO2, NiO and Fe2O3. The polycrystalline ferrites obtained by ceramic route were subjected to the mechanical milling procedure in order to reduce the particles size and to refine de crystallites size. A planetary high energy ball mill Fritch Pulverisette 4 was used and the milling time was up to 120 minutes. The ceramic and as-milled ferrites samples were investigated by X-ray diffraction (XRD), scanning electronic microscopy (SEM) and laser particles size analysis (LPSA). After 15 minutes of milling the mean crystallites size for each one of the nickel-manganese ferrites is in nanometric range. After 120 minutes of mechanical milling for all ferrites types the mean crystallites size is at 6-8 nm, depending on Ni/Mn ratio. According to the SEM and LPSA investigations the milled ferrites powders consists in nanometric particles alongside of the micrometric ones. The micrometric particles are formed by multiple nanocrystallites.

scholarly journals Study of Aluminum Wires Treated with MoB2 Nanoparticles

2018 ◽  
Vol 2 (3) ◽  
pp. 50 ◽  
Author(s):  
David Florián-Algarín ◽  
Angelisse Ramos-Morales ◽  
Michelle Marrero-García ◽  
Oscar Suárez
Keyword(s):  
Pure Aluminum ◽  
High Energy ◽  
Mechanical And Thermal Properties ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
Mechanically Alloyed ◽  
Bending Tests ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
Microstructure Of The Material

This research focuses on the fabrication of aluminum wires treated with MoB2 nanoparticles and their effect on selected mechanical and thermal properties of the wires. These nanoparticles were obtained by fragmentation in a high-energy ball mill and then mechanically alloyed with pure aluminum powder to form Al/MoB2 pellets. The pellets were added to molten pure aluminum (99.5%) at 760 °C. Afterwards, the treated melt was cast into cylindrical ingots, which were cold-formed to the desired final diameter with intermediate annealing. X-ray diffraction and optical microscopy allowed characterizing the structure and microstructure of the material. The wires underwent tensile and bending tests, as well as electrical measurements. Finally, this research demonstrated how the mechanical properties of aluminum wires can be enhanced with the addition of MoB2 nanoparticles with minimal effects on the material resistivity.

The Investigation of Structural and Magnetic Properties at High-Temperature of Nanostructured Fe90-Mg10 Alloys Produced by Mechanical Alloying

2018 ◽  
Vol 54 ◽  
pp. 136-145
Author(s):  
A. El Mohri ◽  
M. Zergoug ◽  
K. Taibi ◽  
M. Azzaz
Keyword(s):  
High Temperature ◽  
Mechanical Alloying ◽  
Milling Time ◽  
High Energy ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
The Mean

Nanocrystalline Fe90Mg10 alloy samples were prepared by mechanical alloying process using planetary high energy ball mill. The prepared powders were characterized using differential thermal analysis (DTA), X-ray diffraction technique (XRD) at high temperature, transmission electron microscopy (TEM), and the vibrating sample magnetometer (VSM). Obtained results are discussed according to milling time. XRD at high temperature results also indicated that when the milling time increases, the lattice parameter and the mean level of grain size increase, whereas the microstrains decrease. The result of the observation by the TEM of the Fe-Mg powders prepared in different milling time, coercive fields derived and Saturation magnetization derived from the hysteresis curves in high temperature are discussed as a function of milling time.

Phase Transformation in Al3Ni2 Alloy during Mechanical Alloying and Heating of Milling Products

2013 ◽  
Vol 203-204 ◽  
pp. 272-275
Author(s):  
Marek Krasnowski ◽  
Tadeusz Kulik
Keyword(s):  
Mechanical Alloying ◽  
Phase Transformations ◽  
Intermetallic Phase ◽  
Diffraction Method ◽  
High Energy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
High Energy Ball Mill ◽  
Elemental Powder Mixture ◽  
Energy Ball

An elemental powder mixture corresponding to the Al3Ni2 phase stoichiometry was subjected to mechanical alloying in a high-energy ball mill. Products of this process after various milling times were investigated by differential scanning calorimetry. The phase transformations occurring in the material throughout milling and during heating in a calorimeter were investigated by X-ray diffraction method. This study revealed that a metastable nanocrystalline NiAl intermetallic phase was formed during the mechanical alloying process. Heating of the synthesised powders in the calorimeter caused phase transformations, the product of which was an equilibrium Al3Ni2 intermetallic phase or a mixture of NiAl, Al3Ni2 and Al3Ni intermetallic phases, depending on the milling time and the temperature up to which the material was heated.

Synthesis of the Fe-10%Si Nanocrystalline Powder by Mechanical Alloying

2014 ◽  
Vol 216 ◽  
pp. 283-287 ◽  
Author(s):  
Cristina Daniela Stanciu ◽  
Traian Florin Marinca ◽  
Florin Popa ◽  
Ionel Chicinaş ◽  
Olivier Isnard
Keyword(s):  
Mechanical Alloying ◽  
High Energy ◽  
Milling Process ◽  
Nanocrystalline Powder ◽  
Alloy Formation ◽  
X Ray Diffraction ◽  
Nanocrystalline State ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
Si Content

Fe-Si alloy with a Si content of 10 wt. % was obtained in nanocrystalline state by mechanical alloying of elemental iron and silicon powders. The mechanical alloying process was carried out in a high energy ball mill (Fritsch, Pulverisette 4) in argon atmosphere. The X-ray diffraction (XRD) studies indicated that after 4 hours of milling the Fe-Si alloy is formed. The mean crystallites size decreases down to 7 nm after 8 hours of milling. The particles morphology investigated by scanning electron microscopy (SEM) showed an evolution during milling process from two different kinds of particles to a one kind of particles with irregular shape. The magnetisation of powders decreases upon increasing the milling time up to 4 hours as a consequence of the Fe-Si alloy formation.

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