Mechanisms of Phase Formation During Milling in the Ternary Immiscible AG-CU-FE System

1995 ◽  
Vol 400 ◽  
Author(s):  
T. Klassen ◽  
U. Herr ◽  
R.S. Averback
Keyword(s):  
Milling Time ◽  
Phase Evolution ◽  
Final States ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Two Phase ◽  
X Ray ◽  
Thermally Activated ◽  
Energetic Model ◽  
Fcc Alloy

AbstractPowder blends consisting of prealloyed FCC Ag-Cu solid solutions and elemental Fe powders were ball milled in overall compositions of Ag25Cu50Fe25, andAg40Cu20Fe40. The phase evolution with milling time was investigated by x-ray diffraction and differential scanning calorimetry. For the sample with higher Cu concentration, a ternary FCC alloy phase was formed, while milling the other sample resulted in a two phase mixture consisting of a Ag-rich FCC and an Fe-rich BCC solid solution. About the same amount of enthalpy between 12 and 13 kJ/g-atom is stored in the final states for the two different compositions. Two models based on kinetic and energetic considerations will be discussed and compared to the results. The kinetic model is based on the competition between forced atomic motion during shearing, which is driving the system towards a homogeneous alloy, and thermally activated diffusion, which favors phase separation. For the energetic model, the energy balance is calculated and a phase transformation is expected, if the required energy can be stored in phase boundaries.

scholarly journals Mechanical Amorphization and Recrystallization of Mn-Co(Fe)-Ge(Si) Compositions

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 534 ◽  
Author(s):  
Antonio Vidal-Crespo ◽  
Jhon J. Ipus ◽  
Javier S. Blázquez ◽  
Alejandro Conde
Keyword(s):  
Room Temperature ◽  
Crystal Size ◽  
Milling Time ◽  
Phase Evolution ◽  
Intermetallic Phases ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Bcc Phase ◽  
Thermal Stability Of

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 differential scanning calorimetry. Room temperature 57Fe Mössbauer spectroscopy was used to follow the changes in the Fe environments. A paramagnetic Co-based amorphous phase developed in both alloys as milling progressed. However, while the presence of Si stabilized the Mn-type phase, mechanical recrystallization was observed in a Si-free composition leading to the formation of a MnCo(Fe)Ge intermetallic (Pnma space group) with a crystal size of 7 ± 1 nm. Mössbauer results indicate that Fe atoms migrate from the initial bcc phase to the amorphous and intermetallic phases.

Microstructure Evolution of a Fine Grain Al-50wt%Si Alloy Fabricated by High Energy Milling

2011 ◽  
Vol 479 ◽  
pp. 54-61 ◽  
Author(s):  
Fei Wang ◽  
Ya Ping Wang
Keyword(s):  
Grain Growth ◽  
Microstructure Evolution ◽  
Room Temperature ◽  
Milling Time ◽  
High Energy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Laser Method ◽  
X Ray ◽  
Fine Grain

Microstructure evolution of high energy milled Al-50wt%Si alloy during heat treatment at different temperature was studied. Scanning electron microscope (SEM) and X-ray diffraction (XRD) results show that the size of the alloy powders decreased with increasing milling time. The observable coarsening of Si particles was not seen below 730°C in the high energy milled alloy, whereas, for the alloy prepared by mixed Al and Si powders, the grain growth occurred at 660°C. The activation energy for the grain growth of Si particles in the high energy milled alloy was determined as about 244 kJ/mol by the differential scanning calorimetry (DSC) data analysis. The size of Si particles in the hot pressed Al-50wt%Si alloy prepared by high energy milled powders was 5-30 m at 700°C, which was significantly reduced compared to that of the original Si powders. Thermal diffusivity of the hot pressed Al-50wt%Si alloy was 55 mm2/s at room temperature which was obtained by laser method.

On the Mechanism of Milling Induced Disordering in AlFe

1996 ◽  
Vol 460 ◽  
Author(s):  
M. T. Clavaguera-Mora ◽  
J. Zhu ◽  
M. Meyer ◽  
L. Mendoza-Zelis ◽  
F. H. Sanchez ◽  
...  
Keyword(s):  
Long Range ◽  
Milling Time ◽  
Continuous Heating ◽  
X Ray Diffraction ◽  
Mechanical Grinding ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Diffusion Controlled ◽  
Transmission Mössbauer Spectroscopy ◽  
Kinetics Of

ABSTRACTThe evolution of the B2-AlFe phase during mechanical grinding in Ar has been examined as a function of milling time by X-Ray diffraction, transmission Mössbauer spectroscopy and differential scanning calorimetry. Short and long range disorder was observed to increase with the mechanical treatment up to the attainment of a steady state. The evolution of the long range order parameter and of the local atomic configurations at Fe sites were analyzed in terms of possible mechanisms for milling induced disordering. The kinetics of the thermal reordering was studied under continuous heating and isothermal calorimetrie regimes. Modeling of the reordering processes by diffusion controlled growth of pre-existing ordered grains is presented as well as the estimated values of both the enthalpy and the activation energy of the reordering process. The results are consistent with a non uniform distribution of disorder throughout the sample and will be compared with preceding information on related systems.

Structure Evolution of La(OH)3 /Fe Composite during Ball Milling

2020 ◽  
Vol 65 ◽  
pp. 123-134
Author(s):  
Samira Lalaoua ◽  
Bouguerra Bouzabata ◽  
Safia Alleg ◽  
Abedelmalik Djekoun ◽  
David Shmool
Keyword(s):  
Ball Milling ◽  
Milling Time ◽  
Magnetic Measurements ◽  
Amorphous Structure ◽  
Structure Evolution ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Composite Powders ◽  
X Ray

Fe-10wt% La (OH)3 composite powders have been fabricated by ball milling, under argon atmosphere for milling periods of 0, 5 and 10 h, respectively. Changes in structural, morphological, thermal and magnetic properties of the powders during mechanical alloying and during subsequent annealing have been examined by X-ray diffraction, scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and vibrating sample magnetometer (VSM). XRD results: showed the formation of new phases (Fe and LaFeO3 perovskite) created through the ball milling. The results showed that the crystalline size of ball milled powders decreased with increasing the milling time. In fact, after 10 h of ball milling, La (OH)3 changes from nanostructure in amorphous structure. The magnetic measurements display a distinct saturation magnetization and coercivity.

Microstructural Transformations of an Amorphous Fe90 Zr10 Alloy Induced by High-Energy Ball-Milling

2006 ◽  
Vol 510-511 ◽  
pp. 698-701
Author(s):  
Pyuck Pa Choi ◽  
Young Soon Kwon ◽  
Ji Soon Kim ◽  
Dae Hwan Kwon
Keyword(s):  
Ball Milling ◽  
Milling Time ◽  
High Energy ◽  
High Energy Ball Milling ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Melt Spun ◽  
Energy Ball ◽  
Induced Crystallization

Mechanically induced crystallization of an amorphous Fe90Zr10 alloy was studied by means of X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Under high-energy ball-milling in an AGO-2 mill, melt-spun Fe90Zr10 ribbons undergo crystallization into BCC α- Fe(Zr). Zr atoms are found to be solved in the Fe(Zr) grains up to a maximum supersaturation of about 3.5 at.% Zr, where it can be presumed that the remaining Zr atoms are segregated in the grainboundaries. The decomposition degree of the amorphous phase increases with increasing milling time and intensity. It is proposed that the observed crystallization is deformation-induced and rather not attribute to local temperature rises during ball-collisions.

Study on Generation of Fine Grained Titanium Aluminide Through Ball Milling of Ti, Al and Ni-P Coated Graphite Powder

2009 ◽  
Vol 67 ◽  
pp. 45-51
Author(s):  
Rohit Kumar Gupta ◽  
Vijaya Agarwala ◽  
Sunayan Thakur ◽  
Ramesh Chandra Agarwala ◽  
Bhanu Pant
Keyword(s):  
Particle Size ◽  
Ball Milling ◽  
Titanium Aluminide ◽  
Milling Time ◽  
Stoichiometric Composition ◽  
High Energy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Final Particle ◽  
X Ray

High energy ball milling (HEBM) had been carried out to produce submicron size titanium aluminide intermetallics (TiAl) using elemental powders of Ti and Al alongwith Ni-P coated graphite. 1% graphite powders was added to stoichiometric composition of Ti48Al and ball milling was conducted for different milling time at varying rpm. The effect of milling time and rpm on particle size has been studied. The prepared samples have been characterized using X-ray diffraction, differential scanning calorimetry (DSC) and scaning elecron microscopy (SEM). Grain size as low as 500 nm could be achieved. Formation of Ti3Al, TiAl and carbon containing intermetallic compounds had been confirmed through X-ray diffraction. Milling time and rpm of mill is found to be important factors which control the final particle size.

Mechanochemical Synthesis and Characterization of FeNi-Al2O3 Nanocomposites

2011 ◽  
Vol 413 ◽  
pp. 109-116 ◽  
Author(s):  
Seyyed Abdalkarim Sajjadi ◽  
Hossein Beygi ◽  
Mansour Zare
Keyword(s):  
Milling Time ◽  
Phase Evolution ◽  
Synthesis And Characterization ◽  
Maximum Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mixture Characterization ◽  
Matrix Nanocomposites ◽  
Scanning Electron

In this Study, FeNi-Al2O3 nanocomposites with three different compositions were successfully synthesized through mechanical alloying of Fe2O3, Ni and Al powders mixture. Characterization of the products was accomplished by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The effect of various parameters such as chemical composition of starting materials, milling time and annealing on the phase evolution, morphology and microhardness of samples was investigated. It was found that FeNi matrix nanocomposites reinforced with 10, 15 and 30wt.% of Al2O3 were fabricated in 300, 240 and 180 min of milling, respectively. The crystallite size of the intermetallic FeNi phase and particle size of Al2O3 in the 720 min milled FeNi-30wt.%Al2O3 nanocomposite sample were calculated 28nm and 5.15 µm, respectively. Microhardness results also showed the same sample had the maximum hardness value of 790 HV.

Structural and Mechanical Properties of Nanostructured Fe-Mn-C Alloys Prepared by Mechanical Alloying

2018 ◽  
Vol 52 ◽  
pp. 80-87 ◽  
Author(s):  
Lounes Belaid ◽  
Meriem Bendoumia ◽  
Mohamed Dakiche ◽  
Hanane Mechri ◽  
Djaffar Dahmoun ◽  
...  
Keyword(s):  
Milling Time ◽  
Milled Powder ◽  
Nanocrystalline Structure ◽  
Hadfield Steel ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Grain Sizes ◽  
New Phase ◽  
High Manganese Austenitic Steel

The object of our research is to combine the properties of Mangalloys and nanoscale advantages in order to enhance the performance and extend the range of applications in the field of work-hardening parts such as railroad components, armor, and modern auto components. We have produced a high-manganese austenitic steel nanomaterial containing more than 12 wt% Mn, which is the level of Mn in Hadfield steel. This study experimentally determined the process of phase transitions involved in Fe–13 wt% Mn–1.2 wt% C alloy during mechano-synthesis and after subsequent annealing. The milling time ranged from 0.5 to 24 h. The unique features of the nanocrystalline structure and the changes in microstructure as a function of milling time were investigated by X-ray diffraction analysis, differential scanning calorimetry, and scanning electron microscopy coupled with EDX. The grain sizes and microstrain of the milled powder were determined. A thorough study has been done on the sample where a new phase fcc (at 24h of MA) was formed.The object of our research is to combine the properties of Mangalloys and nanoscale advantages in order to enhance the performance and extend the range of applications in the field of work-hardening parts such as railroad components, armor, and modern auto components. We have produced a high-manganese austenitic steel nanomaterial containing more than 12 wt% Mn, which is the level of Mn in Hadfield steel. This study experimentally determined the process of phase transitions involved in Fe–13 wt% Mn–1.2 wt% C alloy during mechano-synthesis and after subsequent annealing. The milling time ranged from 0.5 to 24 h. The unique features of the nanocrystalline structure and the changes in microstructure as a function of milling time were investigated by X-ray diffraction analysis, differential scanning calorimetry, and scanning electron microscopy coupled with EDX. The grain sizes and microstrain of the milled powder were determined. A thorough study has been done on the sample where a new phase fcc (at 24h of MA) was formed.

Exothermic reactions in cold-rolled Ni/Al reactive multilayer foils

2008 ◽  
Vol 23 (2) ◽  
pp. 367-375 ◽  
Author(s):  
X. Qiu ◽  
J. Graeter ◽  
L. Kecskes ◽  
J. Wang
Keyword(s):  
Phase Evolution ◽  
Reaction Process ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Exothermic Reactions ◽  
X Ray ◽  
Multilayer Foils ◽  
Cold Rolled ◽  
Two Peaks ◽  
Evolution Sequence

Exothermic reactions in cold-rolled Ni/Al reactive multilayer foils were investigated in this study. A two-stage reaction process was observed in the self-propagating reactions in the cold-rolled foils that were ignited by a point-source flame. Foils taken out of the flame after completing the first stage of the reaction process were compared to those allowed to complete both stages. Differences in the phase-evolution sequence from the two types of foils were studied by differential scanning calorimetry (DSC), using slow and controlled heating of the samples. Several exothermic peaks could be identified from the DSC thermograms for both types of foils. Using the DSC, both the as-cold-rolled and partially reacted foils were heated to each peak temperature to identify the reaction product associated with each peak. X-ray diffraction and scanning electron microscopy analyses showed that the first two peaks corresponded to the formation of Al3Ni, while the third peak corresponded to the formation of AlNi.

The synthesis of NbSi2 by mechanical alloying

1997 ◽  
Vol 12 (5) ◽  
pp. 1172-1175 ◽  
Author(s):  
Taiping Lou ◽  
Guojiang Fan ◽  
Bingzhe Ding ◽  
Zhuangqi Hu
Keyword(s):  
Solid Solution ◽  
Differential Scanning Calorimetry ◽  
Intermetallic Compound ◽  
Mechanical Alloying ◽  
Ball Milling ◽  
Temperature Rise ◽  
Milling Time ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

The stoichiometric intermetallic compound NbSi2 has been synthesized by mechanical alloying (MA) elemental Nb and Si powders. The alloying process has been investigated by means of x-ray diffraction (XRD) and differential scanning calorimetry (DSC). It was found that the formation of the Nb2Si intermetallic compound occurs abruptly after 65 min of milling without any interruptions during the alloying process. However, short interruptions at a 5 min interval during ball milling result in a gradual reaction for the formation of the NbSi2 compound as well as a new metastable bcc structured solid solution. We conclude that the temperature rise during mechanical alloying plays an important role in initiating the abrupt reaction after an incubation milling time.

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