Thermal Stability of Severe Plastically Deformed VT-6 (Ti-6Al-4V)

2008 ◽  
Vol 584-586 ◽  
pp. 893-898 ◽  
Author(s):  
Henry J. Rack ◽  
Javaid Qazi ◽  
L. Allard ◽  
Ruslan Valiev
Keyword(s):  
Thermal Stability ◽  
Volume Fraction ◽  
Tem Analysis ◽  
Β Phase ◽  
Transmission Electron ◽  
Continuous Recrystallization ◽  
Hardness Increase ◽  
Lower Temperature ◽  
The Individual ◽  
Thermal Stability Of

The thermal stability of equal channel angular extruded VT-6(Ti-6Al-4V) has been examined using micro-hardness, nano-hardness of the individual αand β phases backscattered scanning (BSEI) and transmission electron microscopy (TEM). After straining to an equivalent total equivalent of 6.5 samples were annealed for 1 h at temperatures between 175 and 800 o C followed by water quenching. Micro and nano-hardness measurements showed an initial hardness increase, the former rising to a maximum at 175°C, while the latter exhibited a maximum at 500°C. BSEI and TEM analysis showed that these observations can be understood by considering the microstructure changes occurring at different length scales. Annealing in the temperature range of 175 to 500°C did not significantly alter the α and β particle size, while TEM showed that recovery and continuous recrystallization occurred in the α phase, higher temperatures being required to activate the recovery and recrystallization processes within the β phase. Finally at temperatures above 600°C spheroidization and growth of the β phase occurred with the volume fraction of this phase increasing from 15 pct at lower temperature to 25 pct at 800°C, an equi-axed α+ β microstructure being observed at this temperature.

The Influence of the ECAP Temperature on Microstructure and Mechanical Properties of a Magnesium Alloy

2006 ◽  
Vol 503-504 ◽  
pp. 609-614 ◽  
Author(s):  
Olya B. Kulyasova ◽  
Rinat K. Islamgaliev ◽  
Nikolay A. Krasilnikov
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Thermal Stability ◽  
Transmission Electron Microscopy ◽  
Magnesium Alloy ◽  
Volume Fraction ◽  
Angular Pressing ◽  
Transmission Electron ◽  
Significant Difference ◽  
Thermal Stability Of

The influence of the equal channel angular pressing (ECAP) temperature (150-350oC) on microstructure of the AM60 magnesium alloy has been investigated using transmission electron microscopy. It was demonstrated that application of various ECAP regimes leads to significant difference in a grain size and volume fraction of precipitates in investigated material. Thermal stability of precipitates and correlation between microstructure and tensile strength are discussed.

Formation and Thermal Stability of Nd0.32Y0.68Si1.7 Layers Formed by Channeled Ion Beam Synthesis

1998 ◽  
Vol 514 ◽  
Author(s):  
M. F. Wu ◽  
A. Vantomne ◽  
S. Hogg ◽  
H. Pattyn ◽  
G. Langouche ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Ion Beam ◽  
Hexagonal Structure ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Good Crystalline Quality ◽  
Ion Beam Synthesis ◽  
Thermal Stability Of

ABSTRACTThe Nd-disilicide, which exists only in a tetragonal or an orthorhombic structure, cannot be grown epitaxially on a Si(111) substrate. However, by adding Y and using channeled ion beam synthesis, hexagonal Nd0.32Y0.68Si1.7 epilayers with lattice constant of aepi = 0.3915 nm and cepi = 0.4152 nm and with good crystalline quality (χmin of Nd and Y is 3.5% and 4.3 % respectively) are formed in a Si(111) substrate. This shows that the addition of Y to the Nd-Si system forces the latter into a hexagonal structure. The epilayer is stable up to 950 °C; annealing at 1000 °C results in partial transformation into other phases. The formation, the structure and the thermal stability of this ternary silicide have been studied using Rutherford backscattering/channeling, x-ray diffraction and transmission electron microscopy.

scholarly journals Polystyrene/Montmorillonite Nanocomposites: Study of the Morphology and Effects of Sonication Time on Thermal Stability

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Mashael Alshabanat ◽  
Amal Al-Arrash ◽  
Waffa Mekhamer
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Solution Method ◽  
Sonication Time ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Polystyrene Matrix ◽  
Before And After ◽  
Silicate Layers ◽  
Thermal Stability Of

Polymer nanocomposites of polystyrene matrix containing 10% wt of organo-montmorillonite (organo-MMT) were prepared using the solution method with sonication times of 0.5, 1, 1.5, and 2 hours. Cetyltrimethylammonium bromide (CTAB) is used to modify the montmorillonite clay after saturating its surface with Na+ions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the montmorillonite before and after modification by CTAB. The prepared nanocomposites were characterized using the same analysis methods. These results confirm the intercalation of PS in the interlamellar spaces of organo-MMT with a very small quantity of exfoliation of the silicate layers within the PS matrix of all samples at all studied times of sonication. The thermal stability of the nanocomposites was measured using thermogravimetric analysis (TGA). The results show clear improvement, and the effects of sonication time are noted.

Immobilization of hemoglobin on stable mesoporous multilamellar silica vesicles and their activity and stability

2005 ◽  
Vol 20 (10) ◽  
pp. 2682-2690 ◽  
Author(s):  
Yufang Zhu ◽  
Weihua Shen ◽  
Xiaoping Dong ◽  
Jianlin Shi
Keyword(s):  
Thermal Stability ◽  
Pore Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Practical Applications ◽  
Silica Material ◽  
Transmission Electron ◽  
Mesoporous Support ◽  
Adsorption Desorption ◽  
Thermal Stability Of

A stable mesoporous multilamellar silica vesicle (MSV) was developed with a gallery pore size of about 14.0 nm. A simulative enzyme, hemoglobin (Hb), was immobilized on this newly developed MSV and a conventional mesoporous silica material SBA-15. The structures and the immobilization of Hb on the mesoporous supports were characterized with x-ray diffraction, transmission electron microscopy, N2 adsorption-desorption isotherms, Fourier transform infrared, ultraviolet-visible spectroscopy, and so forth. MSV is a promising support for immobilizing Hb due to its large pore size and high Hb immobilization capacity (up to 522 mg/g) compared to SBA-15 (236 mg/g). Less than 5% Hb was leached from Hb/MSV at pH 6.0. The activity study indicated that the immobilized Hb retained most peroxidase activity compared to free Hb. Thermal stability of the immobilized Hb was improved by the proctetive environment of MSV and SBA-15. Such an Hb-mesoporous support with high Hb immobilization capacity, high activity, and enhanced thermal stability will be attractive for practical applications.

Strengthening Mechanism and Thermal Stability of Spray Formed H13 Steel

2019 ◽  
Vol 295 ◽  
pp. 49-56
Author(s):  
Zhan Zhan Zhang ◽  
Wan Zhen Wang ◽  
Yun Bo Chen ◽  
Miao Hui Wang ◽  
Chang De Zhao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Transmission Electron Microscopy ◽  
Strengthening Mechanism ◽  
H13 Steel ◽  
Tempering Temperature ◽  
Transmission Electron ◽  
Tempering Treatment ◽  
Hardness Values ◽  
Thermal Stability Of

The aim of this work is to study the strengthening mechanism and thermal stability of spray formed H13 steel. The microstructure and hardness of spray formed H13 steels are investigated by electron microscopy, transmission electron microscopy and hardness measurementscanning. The calculated results demonstrate that tensile strength, impact energy and hardness values of sprayed-formed H13 steel are higher than that of as-cast H13 steel when the tempering temperature is 600 °C after quenched at 1050 °C. Compared with as-cast H13 steels, tempered spray-formed H13 steels possess supernal high-temperature temper resistant stability. The chemical composition of the carbides in spray-formed steels is V and Cr rich spherical carbides are hardly influenced by the tempering treatment.

Structure and Thermal Stability of Cu after Severe Plastic Deformation

2010 ◽  
Vol 297-301 ◽  
pp. 1312-1321 ◽  
Author(s):  
Vladimir V. Popov ◽  
A.V. Stolbovkiy ◽  
E.N. Popova ◽  
V.P. Pilyugin
Keyword(s):  
Thermal Stability ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
High Pressure Torsion ◽  
Pure Copper ◽  
Nanocrystalline Structure ◽  
Transmission Electron ◽  
Evolution Of Structure ◽  
Stability Of Structure ◽  
Thermal Stability Of

Evolution of structure of high-purity and commercially pure copper at severe plastic deformation (SPD) by high pressure torsion (HPT) at room temperature and in liquid nitrogen has been studied by transmission electron microscopy (TEM) and measurements of microhardness. Thermal stability of structure obtained by HPT has been investigated. Factors preventing from obtaining nanocrystalline structure in Cu are analyzed and possible ways of their overcoming are discussed.

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