Microstructural Evaluation of Boron Free and Boron Containing Heat-Treated Ti-35Nb-7.2Zr-5.7Ta Alloy

2012 ◽  
Vol 18 (2) ◽  
pp. 295-303 ◽  
Author(s):  
Pallab Majumdar
Keyword(s):  
X Ray Diffraction ◽  
Second Stage ◽  
Β Phase ◽  
Solution Treated ◽  
Α Phase ◽  
Treatment Conditions ◽  
Transmission Electron ◽  
Heat Treated ◽  
Microstructural Evaluation ◽  
Diffraction Patterns

AbstractThe microstructure of Ti-35Nb-7.2Zr-5.7Ta (TNZT) and Ti-35Nb-7.2Zr-5.7Ta-0.5B (TNZTB) alloys under different heat treatment conditions has been analyzed. The solution-treated and water-quenched TNZT sample consists mainly of β phase with a very small amount of fine athermal ω precipitate. Precipitation of α can be observed when solution-treated samples are directly aged at 580°C for 8 h. The microstructure of the samples subjected to single-stage aging at 300°C or 400°C consists of ω precipitates in equiaxed β grains. Second stage aging at 580°C for 8 h after first stage of aging at 300°C or 400°C results in the replacement of ω precipitates by secondary α. In all of these samples, the amount of ω or α phase was very small, and therefore they could not be detected by X-ray diffraction studies. However, analysis of selected area diffraction patterns obtained from transmission electron microscopy studies confirms their presence. The addition of boron leads to the formation of dispersed precipitates of TiB in the β matrix of the TNZT alloy and also refines the β grains in the microstructure. However, other microstructural features of the TNZTB alloy are similar to those of the TNZT alloy.

Phase Constitution and Heat Treatment Behavior of Zr-Nb Alloys

2007 ◽  
Vol 561-565 ◽  
pp. 1435-1440 ◽  
Author(s):  
Masahiko Ikeda ◽  
Tsuyoshi Miyazaki ◽  
Satoshi Doi ◽  
Michiharu Ogawa
Keyword(s):  
Heat Treatment ◽  
Elastic Modulus ◽  
Elastic Moduli ◽  
X Ray Diffraction ◽  
Phase Constitution ◽  
X Ray ◽  
Β Phase ◽  
Ω Phase ◽  
Solution Treated ◽  
Α Phase

Phase constitution in the solution-treated and quenched state and the heat treatment behavior were investigated by electrical resistivity, hardness, and elastic modulus measurements, X-ray diffraction, and optical microscopy. Hexagonal martensite and the β phase were identified in the Zr-5mass%Nb alloy. β and ω phases were identified in the Zr-10 and 15mass%Nb alloys, and only the β phase was identified in the Ti-20Nb alloy. Resistivity at RT, Vickers hardness and elastic modulus increased up to 10Nb and then decreased dramatically at 15Nb. Above 15Nb, these values slightly decreased. The elastic moduli for 15Nb and 20Nb were 59.5 and 55.5 GPa, respectively. On isochronal heat treatment, the isothermal ω phase precipitated between 473 and 623 K and then the α phase precipitated in the 10Nb, 15Nb and 20Nb alloys.

Phase Transformation in Binary Titanium-Base Alloys with Metals of the I, IV−VIII Groups

2007 ◽  
Vol 546-549 ◽  
pp. 1349-1354 ◽  
Author(s):  
A.V. Dobromyslov
Keyword(s):  
Electron Microscopy ◽  
Structural Information ◽  
Eutectoid Decomposition ◽  
X Ray Diffraction ◽  
Minimum Concentration ◽  
X Ray ◽  
Β Phase ◽  
Ω Phase ◽  
Α Phase ◽  
Transmission Electron

Martensitic β→α′(α″) transformation, β→ω transformation and eutectoid decomposition in a series of Ti-base alloys with d transition metals of Groups I, IV-VIII have been investigated using the techniques of X-ray diffraction, optical and transmission electron microscopy. Phase and structural information is given on the non-equilibrium and metastable modifications occurring in these alloys after quenching from high-temperature β-field and aging. The conditions of the orthorhombic α″-phase, ω-phase and metastable β-phase formation in binary titanium–base alloys with d-metals of V-VIII groups were investigated. It was established that the position of the alloying metal in the Periodic Table defines the presence or absence of the α″-phase in the alloy after quenching and the minimum concentration of the alloying metal necessary for formation of the α″-phase, ω-phase and metastable β-phase.

Phase Evolution During Crystallization of an Amorphous TiAl Film

2002 ◽  
Vol 754 ◽  
Author(s):  
O.N. Senkov ◽  
M.D. Uchic
Keyword(s):  
Physical Vapor Deposition ◽  
Phase Evolution ◽  
Grain Structure ◽  
Spherical Particles ◽  
Continuous Heating ◽  
X Ray Diffraction ◽  
Amorphous Phases ◽  
Β Phase ◽  
Α Phase ◽  
Transmission Electron

ABSTRACTPhase evolution during crystallization of an amorphous TiAl film produced by physical vapor deposition (PVD) was studied using differential thermal analysis (DTA), x-ray diffraction (XRD), and transmission electron microscopy (TEM). The following sequence of phase transformations was observed during continuous heating from room temperature: amorphous → body centered cubic (β) → hexagonal close-packed (α) → tetragonal (γ) → ordered α2. The β phase was formed as near-spherical particles that were evenly distributed in the amorphous phase, and the size of these particles was approximately 90 nm. Formation of the α phase by decomposition of β and the remaining amorphous phases led to a very fine feathery-like microstructure arranged in colonies of approximately 100 nm in size. The transformation of the metastable α phase into a mixture of the γ and α2 phases led to formation of an equiaxed γ-grain structure with a grain size of about 150 nm after heating to 850°C.

Effects on Microstructure and Corrosion Behavior of a Heat Treated CuZn36Pb2 Brass

2020 ◽  
Vol 405 ◽  
pp. 333-338
Author(s):  
Roland Haubner ◽  
Susanne Strobl ◽  
Paul Linhardt
Keyword(s):  
Heat Treatment ◽  
Phase Diagram ◽  
Sea Water ◽  
X Ray Diffraction ◽  
Corrosion Tests ◽  
X Ray ◽  
Fine Grained ◽  
Β Phase ◽  
Α Phase ◽  
Heat Treated

The brass CuZn36Pb2 is widely used for fittings, valves and other installation materials. Failures are observed occasionally caused by corrosion. Considering the Cu-Zn phase diagram only α-phase exists in the range of 650 and 300 °C. At higher temperatures α- and β-phase is stable and at lower temperatures α- and β´-phase exist. Since the β-phase is Zn-enriches, it is attacked severely by corrosion. In the recent work brass samples were heat treated at temperatures between 850 and 200 °C to study the microstructural changes and the corresponding electrochemical properties. Potentiostatic corrosion tests were applied in artificial fresh water and sea water at different potential settings. After a heat treated at 850 °C the brass has formed b-phase which can be shown by metallography. At lower temperatures the microstructure is fine grained and no β-phase was observed. To verify the presence of β´-phase a heat treatment at 200 °C was performed but no β´-phase was observed, which was confirmed additionally by X-ray diffraction. Again, after corrosion tests the samples were investigated by metallography and the β-phase was obviously more attacked than the α-phase.

Synthesis and Characterization of Si3N4 Nanopowder by RF Induction Thermal Plasma

2017 ◽  
Vol 898 ◽  
pp. 1597-1602 ◽  
Author(s):  
Xuan Zhao ◽  
Hai Yan Chen ◽  
Chen Yang Shu ◽  
Li Hua Dong ◽  
Yan Sheng Yin
Keyword(s):  
Electron Microscopy ◽  
Thermal Plasma ◽  
X Ray Diffraction ◽  
N Source ◽  
Α Phase ◽  
Induction Thermal Plasma ◽  
Transmission Electron ◽  
Heat Treated ◽  
Different Temperatures

Nano-Si3N4 has been synthesized by the thermal plasma with silicon tetrachloride (SiCl4) as the Si source, liquid ammonia (NH3) as the N source, and silane (SiH4) as the catalyst. And the prepared Nano-Si3N4was heat-treated atfour different temperatures of 1350°C, 1400°C, 1450°C, 1500°C. The as-prepared samples were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR). The results showed that the particle size of the nano-Si3N4 powder was less than 100 nm and it was amorphous when the temperature below 1450°C. At 1500°C, the synthesized Si3N4 powder with the grain size of 10 nm was crystallized, and the α-phase Si3N4 reached more than 90%.

Mechanical Alloying Behavior in the Nb-Si, Ta-Si, and Nb-Ta-Si Systems

1988 ◽  
Vol 133 ◽  
Author(s):  
K. S. Kumar ◽  
S. K. Mannan
Keyword(s):  
High Temperature ◽  
Mechanical Alloying ◽  
Mechanical Milling ◽  
Room Temperature ◽  
Crystalline Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Α Phase

ABSTRACTThe mechanical alloying behavior of elemental powders in the Nb-Si, Ta-Si, and Nb-Ta-Si systems was examined via X-ray diffraction. The line compounds NbSi2 and TaSi2 form as crystalline compounds rather than amorphous products, but Nb5Si3 and Ta5Si3, although chemically analogous, respond very differently to mechanical milling. The Ta5Si3 composition goes directly from elemental powders to an amorphous product, whereas Nb5Si3 forms as a crystalline compound. The Nb5Si3 compound consists of both the tetragonal room-temperature α phase (c/a = 1.8) and the tetragonal high-temperature β phase (c/a = 0.5). Substituting increasing amounts of Ta for Nb in Nb5Si3 initially stabilizes the α-Nb5Si3 structure preferentially, and subsequently inhibits the formation of a crystalline compound.

scholarly journals Microstructure and properties of nano-laminated Y3Si2C2 ceramics fabricated via in situ reaction by spark plasma sintering

2021 ◽  
Vol 10 (3) ◽  
pp. 578-586
Author(s):  
Lin-Kun Shi ◽  
Xiaobing Zhou ◽  
Jian-Qing Dai ◽  
Ke Chen ◽  
Zhengren Huang ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Atomic Scale ◽  
Max Phase ◽  
X Ray Diffraction ◽  
Selected Area Electron Diffraction ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Spark Plasma ◽  
Diffraction Patterns

AbstractA nano-laminated Y3Si2C2 ceramic material was successfully synthesized via an in situ reaction between YH2 and SiC using spark plasma sintering technology. A MAX phase-like ternary layered structure of Y3Si2C2 was observed at the atomic-scale by high resolution transmission electron microscopy. The lattice parameters calculated from both X-ray diffraction and selected area electron diffraction patterns are in good agreement with the reported theoretical results. The nano-laminated fracture of kink boundaries, delamination, and slipping were observed at the tip of the Vickers indents. The elastic modulus and Vickers hardness of Y3Si2C2 ceramics (with 5.5 wt% Y2O3) sintered at 1500 °C were 156 and 6.4 GPa, respectively. The corresponding values of thermal and electrical conductivity were 13.7 W·m-1·K-1 and 6.3×105 S·m-1, respectively.

Cetyltrimethylammonium bromide- and ethylene glycol-assisted preparation of mono-dispersed indium oxide nanoparticles using hydrothermal method

2014 ◽  
Vol 68 (8) ◽  
Author(s):  
Selvakumar Dhanasingh ◽  
Dharmaraj Nallasamy ◽  
Saravanan Padmanapan ◽  
Vinod Padaki
Keyword(s):  
Ethylene Glycol ◽  
Hydrothermal Method ◽  
Indium Oxide ◽  
Cetyltrimethylammonium Bromide ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Transmission Electron ◽  
Diffraction Patterns

AbstractThe influence of cetyltrimethylammonium bromide and ethylene glycol on the size and dispersion of indium oxide nanoparticles prepared under hydrothermal conditions was investigated. The precursor compound, indium hydroxide, obtained by the hydrothermal method in the absence as well as the presence of cetyltrimethylammonium bromide, was converted to indium oxide by sintering at 400°C. The formation of nanoscale indium oxide upon sintering was ascertained by the characteristic infrared adsorption bands and X-ray diffraction patterns of indium oxide. Transmission electron microscopy and band gap values confirmed that the cetyltrimethylammonium bromide facilitated the formation of indium oxide nanoparticles smaller in size and narrower in distribution than those prepared without the assistance of cetyltrimethylammonium bromide.

Influence of Alloying Additions on Enhancement of Soft Magnetic Properties Effect and Crystallization in FeXSiB (X=Cu, V, Co, Zr, Nb) Amorphous Alloys

2007 ◽  
Vol 130 ◽  
pp. 171-174 ◽  
Author(s):  
Z. Stokłosa ◽  
G. Badura ◽  
P. Kwapuliński ◽  
Józef Rasek ◽  
G. Haneczok ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Crystallization Process ◽  
Annealing Temperature ◽  
Magnetic Measurements ◽  
X Ray Diffraction ◽  
Soft Magnetic ◽  
X Ray ◽  
Second Stage ◽  
Transmission Electron

The crystallization and optimization of magnetic properties effects in FeXSiB (X=Cu, V, Co, Zr, Nb) amorphous alloys were studied by applying X-ray diffraction methods, high resolution transmission electron microscopy (HRTEM), resistometric and magnetic measurements. The temperatures of the first and the second stage of crystallization, the 1h optimization annealing temperature and the Curie temperature were determined for different amorphous alloys. Activation energies of crystallization process were obtained by applying the Kissinger method. The influence of alloy additions on optimization effect and crystallization processes was carefully examined.

Facile Refluxing Synthesis of Hydroxyapatite Nanoparticles

2015 ◽  
Vol 68 (8) ◽  
pp. 1293 ◽  
Author(s):  
Pakvipar Chaopanich ◽  
Punnama Siriphannon
Keyword(s):  
Crystallite Size ◽  
Reaction Times ◽  
Single Step ◽  
Hydroxyapatite Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Aqueous Mixture ◽  
Diffraction Patterns ◽  
Microscopy Images

Hydroxyapatite (HAp) nanoparticles were successfully synthesized from an aqueous mixture of Ca(NO3)2·4H2O and (NH4)2HPO4 by a facile single-step refluxing method using polystyrene sulfonate (PSS) as a template. The effects of reaction times, pH, and PSS concentration on the HAp formation were investigated. It was found that the crystalline HAp was obtained under all conditions after refluxing the precursors for 3 and 6 h. The longer refluxing time, the greater the crystallinity and the larger the crystallite size of the HAp nanoparticles. The HAp with poor crystallinity was obtained at pH 8.5; however, the well-crystallized HAp was obtained when reaction pH was increased to 9.5 and 10.5. In addition, the X-ray diffraction patterns revealed that the presence of PSS template caused the reduction of HAp crystallite size along the (002) plane from 52.6 nm of non-template HAp to 43.4 nm and 41.4 nm of HAp with 0.05 and 0.2 wt-% PSS template, respectively. Transmission electron microscopy images of the synthesized HAp revealed the rod-shaped crystals of all samples. The synthesized HAp nanoparticles were modified by l-aspartic acid (Asp) and l-arginine (Arg), having negative and positive charges, respectively. It was found that the zeta potential of HAp was significantly changed from +5.46 to –24.70 mV after modification with Asp, whereas it was +4.72 mV in the Arg-modified HAp. These results suggested that the negatively charged amino acid was preferentially adsorbed onto the synthesized HAp surface.

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