The formation of metastable Ti–Al solid solutions by mechanical alloying and ball milling

1993 ◽  
Vol 8 (11) ◽  
pp. 2819-2829 ◽  
Author(s):  
M. Oehring ◽  
T. Klassen ◽  
R. Bormann
Keyword(s):  
Solid Solution ◽  
Mechanical Alloying ◽  
Ball Milling ◽  
Intermetallic Compounds ◽  
Phase Formation ◽  
Milling Process ◽  
Study Phase ◽  
Phase Selection ◽  
Powder Blends ◽  
Al Powder

Elemental Ti–Al powder blends were mechanically alloyed in order to study phase formation during the alloying process. In addition, the stability of intermetallic phases upon milling was investigated separately in order to determine the origins of phase selection during the milling process. It was found that by mechanical alloying of powder blends, as well as by ball milling of Ti-aluminides for long milling times, the same metastable phases were formed for corresponding compositions, i.e., the hep solid solution for Al concentrations up to 60 at. % and the fcc solid solution for 75 at. % Al. X-ray diffraction (XRD) analyses indicated that the process of mechanical alloying occurred via the diffusion of Al into Ti. By lowering the milling intensity, a two-phase mixture of the hcp solid solution and the amorphous phase was observed for Ti50Al50 and confirmed by transmission electron microscopy (TEM). The results show that phase selection in the final state during mechanical alloying of Ti–Al powder blends and milling of intermetallic compounds is mainly determined by the energetic destabilization of the competing phases caused by the milling process. The destabilization is most pronounced in the case of intermetallic compounds due to the decrease in long-range order upon milling. For the final milling stage, phase formation can be predicted by considering the relative stabilities of the respective phases calculated by the CALPHAD method using the available thermodynamic data for the Ti–Al system.

Influence of Rotating Speed on Mechanical Alloying Behavior of the Elemental Powder Blends of Nb-Ti-Si Based Alloy during Ball Milling Process

2015 ◽  
Vol 816 ◽  
pp. 310-315
Author(s):  
Li Jing Zhang ◽  
Xi Ping Guo
Keyword(s):  
Mechanical Alloying ◽  
Ball Milling ◽  
Lamellar Microstructure ◽  
Milling Process ◽  
Elemental Powder ◽  
Nominal Composition ◽  
Rotating Speed ◽  
Phase Constituent ◽  
Powder Blends ◽  
Speed Up

The elemental powder mixtures with the nominal composition of Nb-20Ti-15Si-5Cr-3Hf-3Al (at. %) were ball milled via QM-1SP4-CL planetary ball-milling machine at different rotating speed (300, 400 and 500 rpm). The corresponding mechanical alloying behaviors of the powder blends, including the evolutions of their phase constituent, microstructure, size and morphology, have been analyzed by XRD, SEM and EDS. The results showed that with increasing rotating speed, the particle was remarkably refined and spheroidized, and meanwhile, the grain size decreased, accompanied with an improved microstrain. Herein, a lamellar microstructure of particles formed at the rotating speed of 300 rpm, and became finer with increasing the rotating speed up to 400 rpm. When further increasing the rotating speed up to 500 rpm, the homogenous microstructure composed of a supersaturated Nb solid solution (Nbss) finally formed.

scholarly journals The Mechanical Alloying Behavior of Fe2O3 into NiO in the High-Energy Ball-Milling Process

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Y. Z. Zhu ◽  
Y. Liu ◽  
H. Huang ◽  
Y. Y. Guo ◽  
S. Y. Yin ◽  
...  
Keyword(s):  
Solid Solution ◽  
Mechanical Alloying ◽  
Ball Milling ◽  
Microstructure Evolution ◽  
Lattice Distortion ◽  
High Energy ◽  
Milling Process ◽  
High Energy Ball Milling ◽  
Sintering Process ◽  
Energy Ball

The NiO and Fe2O3 powders were mixed by the high-energy ball-milling, followed by a sintering of the mixture at 1340°C for 0.5 h. XRD, SEM, DSC, and size measurements were preformed to study the microstructure evolution in the high-energy ball-milled mixture and the sintered ones, as well. It showed that the high-energy ball-milling processes resulted in a severe lattice distortion in the powder of Fe2O3, but only a slight lattice distortion in NiO. Meanwhile, a solid solution of iron atoms into the NiO lattice was also detected in the milling process. It was also found that the solubility of the iron atoms into the NiO lattice delayed the synthesizing reaction in the following sintering process.

Mechanical alloying of Fe and V powders: Intermixing and amorphous phase formation

1989 ◽  
Vol 4 (6) ◽  
pp. 1450-1455 ◽  
Author(s):  
B. Fultz ◽  
G. Le Caür ◽  
P. Matteazzi
Keyword(s):  
Chemical Composition ◽  
Mechanical Alloying ◽  
Ball Milling ◽  
Amorphous Phase ◽  
Phase Formation ◽  
Mössbauer Spectrometry ◽  
Microstructural Changes ◽  
X Ray ◽  
Mossbauer Spectrometry ◽  
Amorphous Phase Formation

Mössbauer spectrometry and x-ray diffractometry were used to characterize the microstructural changes that occurred during the mechanical alloying of Fe and V powders, After 3 h of essentially no interatomic intermixing, an Fe–V alloy began to form. At first the chemical composition of this alloy was highly inhomogeneous, having large variations over distance scales of less than 100 Å. After about 24 h of ball milling, the alloy homogenized and then became at least partly amorphous.

Formation of eutectic RuAl/Ru nanocomposite by mechanical alloying and subsequent annealing

2001 ◽  
Vol 16 (9) ◽  
pp. 2459-2462 ◽  
Author(s):  
K. W. Liu ◽  
F. Mücklich ◽  
R. Birringer
Keyword(s):  
Solid Solution ◽  
Differential Scanning Calorimetry ◽  
Mechanical Alloying ◽  
Heat Release ◽  
Eutectic Composition ◽  
Scanning Calorimetry ◽  
Powder Mixtures ◽  
Al Powder ◽  
Al Matrix ◽  
Milled Powders

No abrupt reaction was observed during mechanical alloying (MA) of Ru and Al powder mixtures with an eutectic composition (Ru70Al30). As-milled powders constitute mainly a Ru(Al) solid solution and/or mixture (matrix), and a very small quantity of RuAl. The complete reaction between Ru and Al during MA was speculated to be hampered by excess Ru in Ru70Al30. No exothermic heat release was detected in differential scanning calorimetry for as-milled powders. Precipitation of RuAl from as-milled Ru(Al) matrix was observed after annealing at various temperatures. The phase fraction of Ru and RuAl reaches an approximately equilibrium value after annealing at 1173 K.

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.

Formation kinetics of nanocrystalline Fe–4 wt.% Al solid solution during ball milling

1997 ◽  
Vol 12 (6) ◽  
pp. 1429-1432 ◽  
Author(s):  
H. G. Jiang ◽  
R. J. Perez ◽  
M. L. Lau ◽  
E. J. Lavernia
Keyword(s):  
Solid Solution ◽  
Ball Milling ◽  
Structural Evolution ◽  
Milling Process ◽  
Avrami Equation ◽  
Scanning Calorimetry ◽  
Diffusion Controlled ◽  
Interphase Boundaries ◽  
Kinetics Of Formation ◽  
Kinetics Of

Formation of nanocrystalline Fe–4 wt.% Al solid solution has been achieved through SPEX ball milling of blended elemental Fe and Al powders. Differential scanning calorimetry (DSC) and x-ray diffraction (XRD) have been employed to follow the structural evolution during the ball-milling process. Exothermic peaks exhibited in DSC diagrams of the powders milled for 10 to 60 min yielded thermal enthalpies corresponding to the formation of Fe–4 wt.% Al solid solution, from which the kinetics of formation were found to follow the Johnson–Mehl–Avrami equation. Assessment of the kinetic parameter n reveals a diffusion controlled mechanism, in which grain and interphase boundaries may play a crucial role, during the solid solution formation of Fe–4 wt.% Al.

Research of Milling Technique on V/Si by Mechanical Alloying

2014 ◽  
Vol 881-883 ◽  
pp. 1479-1482
Author(s):  
Bo Zhang
Keyword(s):  
Solid Solution ◽  
Mechanical Alloying ◽  
Ball Milling ◽  
Particle Shape ◽  
Amorphous State ◽  
Milling Machine ◽  
Change Of Microstructure

V/Si binary powders were mechanical alloyed in ball milling machine. The change of microstructure of V/Si powders during mechanical alloying was investigated. The results showed that during ball milling, the size of mixture powders was reduced gradually and the particle shape transited to a ball. Silicon atoms dissolved in vanadium lattice to be a solid solution. The crystal powders were eventually to amorphous state.

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