The Features of Structure Formation in Mechanically Activated Powder Mixture 3Ti+Al in the Thermal Explosion Mode

2014 ◽  
Vol 621 ◽  
pp. 71-76 ◽  
Author(s):  
V.Y. Filimonov ◽  
Alexander Andreevich Sitnikov ◽  
V.I. Yakovlev ◽  
Marina V. Loginova ◽  
A.V. Afanasyev ◽  
...  
Keyword(s):  
Structure Formation ◽  
Thermal Explosion ◽  
Phase Formation ◽  
Powder Mixture ◽  
Single Phase ◽  
Thermal Relaxation ◽  
Phase Compound ◽  
Characteristic Features ◽  
Equilibrium Defects ◽  
High Frequency Induction

The experimental investigation of structure formation processes in preliminary mechanically activated powder mixture 3Ti + Al was carried out. The synthesis was realized in the thermal explosion mode with the use of high-frequency induction heating. The characteristic features of structure and phase formation in this system by quenching of the mixture at different annealing times were installed. It was shown, that the processes of structure-phase formation occur in the following sequence: chemical reaction - structural relaxation - thermal relaxation - thermal equilibrium. The time-temperature intervals of Ti3Al strictly single-phase compound existence with various concentrationsof non-equilibrium defects of the structure were established.

Analysis of the Influence of High Temperature Synthesis Parameters on the Structure Formation in the Mechanically Activated 3Ti+Al Powder Mixture

2015 ◽  
Vol 788 ◽  
pp. 117-122 ◽  
Author(s):  
Marina V. Loginova ◽  
Valeriy Yu. Filimonov ◽  
Vladimir I. Yakovlev ◽  
Alexander A. Sytnikov ◽  
Alexey Z. Negodyaev ◽  
...  
Keyword(s):  
High Temperature ◽  
Structure Formation ◽  
Powder Mixture ◽  
Heating Temperature ◽  
Optimal Time ◽  
Temperature Synthesis ◽  
Synthesis Parameters ◽  
High Temperature Synthesis ◽  
Phase Compound ◽  
Adiabatic Combustion Temperature

The influence of basic high-temperature synthesis parameters on the process of structure formation in the mechanically activated powder mixture 3Ti+Al was investigated in the study. The synthesis was realized by the method of induction heating in the thermal explosion mode. The heating temperature of the mixture reached 1500°C during the solid state reaction. This temperature exceeded the adiabatic combustion temperature. The investigations of the phase structure formation processes were conducted by XRD methods. In order to obtain a Ti3Al single-phase compound, the optimal time-temperature parameters of the synthesis were determined.

A review on phase prediction in high entropy alloys

2021 ◽  
pp. 095440622110089
Author(s):  
Vinay Kumar Soni ◽  
S Sanyal ◽  
K Raja Rao ◽  
Sudip K Sinha
Keyword(s):  
Solid Solution ◽  
Phase Formation ◽  
Single Phase ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
Modeling Tools ◽  
High Entropy ◽  
Recent Developments ◽  
Phase Prediction ◽  
The Stability

The formation of single phase solid solution in High Entropy Alloys (HEAs) is essential for the properties of the alloys therefore, numerous approach were proposed by many researchers to predict the stability of single phase solid solution in High Entropy Alloy. The present review examines some of the recent developments while using computational intelligence techniques such as parametric approach, CALPHAD, Machine Learning etc. for prediction of various phase formation in multicomponent high entropy alloys. A detail study of this data-driven approaches pertaining to the understanding of structural and phase formation behaviour of a new class of compositionally complex alloys is done in the present investigation. The advantages and drawbacks of the various computational are also discussed. Finally, this review aims at understanding several computational modeling tools complying the thermodynamic criteria for phase formation of novel HEAs which could possibly deliver superior mechanical properties keeping an aim at advanced engineering applications.

EFFECT OF BARIUM ON DIELECTRIC, FERROELECTRIC, IMPEDANCE AND ELECTRICAL MODULUS PROPERTIES OF Bi0.5Na0.5TiO3 CERAMICS

2011 ◽  
Vol 25 (22) ◽  
pp. 2931-2948 ◽  
Author(s):  
K. SAMBASIVA RAO ◽  
K. CH. VARADA RAJULU ◽  
B. TILAK
Keyword(s):  
Power Law ◽  
Single Phase ◽  
Low Frequency ◽  
Rhombohedral Structure ◽  
Conductivity Spectrum ◽  
X Ray ◽  
Impedance Spectroscopy Study ◽  
Conventional Sintering ◽  
Phase Compound ◽  
Jonscher’S Power Law

Perovskite structured ferroelectric ( Na 1/2 Bi 1/2)0.945 Ba 0.055 TiO 3 (BNBT-5.5) material has been synthesized by the conventional sintering technique. X-ray analysis on the material showed a single phase compound with rhombohedral structure with lattice parameters a = 3.89 Åand α = 89.893 Å. Frequency and temperature dependence of dielectric permittivity, impedance, modulus and conductivity have been performed in the frequency and temperature range 45 Hz–5 MHz and 35–595°C, respectively. The observed low frequency dielectric dispersion (LFDD) in the material could be explained by Jonschers power law and evaluated activation energies at different temperature regions. Impedance spectroscopy study showed the presence of both bulk and grain boundary effects in the materials. The ac conductivity spectrum obeyed the Jonscher's power law. Modulus analysis indicated the possibility of hopping mechanism for electrical process in the system.

Role of size, alio-/multi-valency and non-stoichiometry in the synthesis of phase-pure high entropy oxide (Co,Cu,Mg,Na,Ni,Zn)O

2020 ◽  
Vol 49 (21) ◽  
pp. 7123-7132 ◽  
Author(s):  
Nandhini J. Usharani ◽  
Rajat Shringi ◽  
Harshil Sanghavi ◽  
S. Subramanian ◽  
S. S. Bhattacharya
Keyword(s):  
Phase Formation ◽  
Single Phase ◽  
High Entropy ◽  
Phase Pure ◽  
Single Phase Formation

Presence of multivalency/non-stoichiometry to accommodate a different-sized cation and maintaining electroneutrality were identified as the critical criteria for single-phase formation in multicomponent/high entropy systems.

Characterization of NiTi Shape Memory Alloy Sintered at Different Temperatures in Reducing Environment

2020 ◽  
Vol 1010 ◽  
pp. 632-637
Author(s):  
Hafizah Hanim Mohd Zaki ◽  
Nur Azemuzahir Mohd Sobri ◽  
Jamaluddin Abdullah ◽  
Norshahida Sariffudin ◽  
Farah Diana Mohd Daud
Keyword(s):  
Solid State ◽  
Shape Memory ◽  
Phase Formation ◽  
Single Phase ◽  
Reducing Agent ◽  
Niti Shape Memory Alloy ◽  
Transformation Behavior ◽  
Formidable Challenge ◽  
Different Temperatures ◽  
Reducing Environment

NiTi has received significant interest as medical implant materials due to its shape memory effect behavior apart from its good biocompatibility and mechanical properties. The formidable challenge of obtaining single phase NiTi from elemental powders via solid state is due to oxidation problem of elemental powders and the oxygen atoms dissolve in NiTi matrix as interstitial impurities forming stable oxygen-rich TiNiOx. This may deterioriate the shape memory behavior of NiTi. This research investigates the use of MgH2 in combination with CaH2 as in-situ reducing agent to eliminate oxidation of the specimen during sintering both at lower and higher sintering temperatures. Here, the effect of sintering temperature on phase formation and transformation behavior of NiTi in reducing environment was studied. The phase formation was characterized by using x-ray diffraction (XRD) where the morphology and elemental analysis were characterized by using the scanning electron microscope (SEM) equipped with EDS. The martensitic transformation behavior was analyzed using differential scanning calorimeter (DSC). The use of MgH2 and CaH2 as reducing agent has a significant influence on the phase formation of NiTi synthesized via solid state especially at 930 °C, where almost single phase NiTi was formed with good transformation behavior. This reducing agent creates a conducive environment for the production of single phase NiTi.

scholarly journals Study of multiferroic properties of Bi2Fe2WO9 ceramic for device application

2016 ◽  
Vol 06 (03) ◽  
pp. 1650023 ◽  
Author(s):  
Jyoshna Rout ◽  
R. N. P. Choudhary
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Electrical Parameters ◽  
Orthorhombic Crystal ◽  
Solid State Reaction Technique ◽  
X Ray ◽  
Universal Power Law ◽  
Phase Compound ◽  
Comprehensive Study

The Bi2Fe2WO9 ceramic was prepared using a standard solid-state reaction technique. Preliminary analysis of X-ray diffraction pattern revealed the formation of single-phase compound with orthorhombic crystal symmetry. The surface morphology of the material captured using scanning electron microscope (SEM) exhibits formation of a densely packed microstructure. Comprehensive study of dielectric properties showed two anomalies at 200[Formula: see text]C and 450[Formula: see text]C: first one may be related to magnetic whereas second one may be related to ferroelectric phase transition. The field dependent magnetic study of the material shows the existence of small remnant magnetization ([Formula: see text]) of 0.052[Formula: see text]em[Formula: see text]/g at room temperature. The existence of magneto-electric (ME) coupling coefficient along with above properties confirms multi-ferroic characteristics of the compound. Selected range temperature and frequency dependent electrical parameters (impedance, modulus, conductivity) of the compound shows that electric properties are correlated to its microstructure. Detailed studies of frequency dependence of ac conductivity suggest that the material obeys Jonscher’s universal power law.

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