Microstructure and Stabiulty of TiB2 and Cu Multilayers

1990 ◽  
Vol 187 ◽  
Author(s):  
S. N. Basu ◽  
K. M. Hubbard ◽  
J-P. Hirvonen ◽  
T. E. Mitchell ◽  
M. Nastasi
Keyword(s):  
Driving Force ◽  
Multilayer Structure ◽  
Maximum Dose ◽  
Ion Irradiation ◽  
High Strength ◽  
Interfacial Reactions ◽  
Interfacial Stability ◽  
Thermodynamic Driving Force

AbstractThe Interfacial stability of a high strength TiB2/Cu multilayer structure was examined by subjecting the layers to ion irradiation by 400 keV Ne++ ions up to a maximum dose of 12×1015 ions/cm2. Even at the highest dose, with a maximum dpa value of 4.92, the TiB2/Cu interface did not show any mixing. This stability of the multilayers has been explained by examining the maximum thermodynamic driving force for Interfacial reactions in this system.

Nucleation Mechanism of IGF in the HAZs of Ti-Killed HSLA Steel

2014 ◽  
Vol 898 ◽  
pp. 161-163
Author(s):  
Dong Ming Duan ◽  
Meng Xia Tang ◽  
Run Wu ◽  
Yong Bu ◽  
Xiao Chen
Keyword(s):  
Electron Microscope ◽  
Driving Force ◽  
Hsla Steel ◽  
High Strength ◽  
Nucleation Mechanism ◽  
Titanium Oxides ◽  
Lattice Matching ◽  
Transmission Electron ◽  
Thermodynamic Driving Force ◽  
Inert Substrate

The weldability of the steel can be improved by formation of intra-granular ferrite (IGF) in heat affected zones (HAZs) on the edge of weld bead. The nucleation mechanism of IGF of Ti-killed high strength low alloyed (HSLA) steel has already been investigated with the aid of transmission electron microscope. Titanium oxides (Ti2O3) particles with the diameter of 0.4μm and Si-rich complex inclusions (Ti3O5+MnS) with that of 0.5μm can serve as the nuclei of IGF. The nucleation mechanism of IGF is proposed as follows: (1) inclusions are inert substrate. (2) The depletion of the austenite former Mn local to the inclusion increases the thermodynamic driving force of γα for transformation. (3) Lattice matching between inclusion and ferrite reduces the interfacial energy of opposing nucleation.

scholarly journals Ion Irradiation-Induced Microstructural Evolution of Ni–Mo–Cr Low Alloy Steels

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2268
Author(s):  
Hongying Sun ◽  
Penghui Lei ◽  
Guang Ran ◽  
Hui Wang ◽  
Jiyun Zheng ◽  
...  
Keyword(s):  
Irradiation Dose ◽  
Focused Ion Beam ◽  
Ion Irradiation ◽  
Ion Beam ◽  
High Strength ◽  
Positron Annihilation Spectroscopy ◽  
Small Scale ◽  
Low Alloy Steels ◽  
Dislocation Loops ◽  
S Parameter

As leading candidates of sheet steels for advanced nuclear reactors, three types of Ni–Mo–Cr high-strength low alloy (HSLA) steels named as CNST1, CNST2 and CNSS3 were irradiated by 400 keV Fe+ with peak fluence to 1.4 × 1014, 3.5 × 1014 and 7.0 × 1014 ions/cm2, respectively. The distribution and morphology of the defects induced by the sample preparation method and Fe+ irradiation dose were investigated by transmission electron microscopy (TEM) and positron-annihilation spectroscopy (PAS). TEM samples were prepared with two methods, i.e., a focused ion beam (FIB) technique and the electroplating and twin-jet electropolishing (ETE) method. Point defects and dislocation loops were observed in CNST1, CNST2 and CNSS3 samples prepared via FIB. On the other hand, samples prepared via the ETE method revealed that a smaller number of defects was observed in CNST1, CNST2 and almost no defects were observed in CNST3. It is indicated that artifact defects could be introduced by FIB preparation. The PAS S-W plots showed that the existence of two types of defects after ion implantation included small-scale defects such as vacancies, vacancy clusters, dislocation loops and large-sized defects. The S parameter of irradiated steels showed a clear saturation in PAS response with increasing Fe+ dose. At the same irradiation dose, higher values of the S-parameter were achieved in CNST1 and CNST2 samples when compared to that in CNSS3 samples. The mechanism and evolution behavior of irradiation-induced defects were analyzed and discussed.

scholarly journals Thermodynamic driving force of transient negative capacitance of ferroelectric capacitors

2021 ◽  
Vol 119 (2) ◽  
pp. 022901
Author(s):  
Yuanyuan Zhang ◽  
Xiaoqing Sun ◽  
Junshuai Chai ◽  
Hao Xu ◽  
Xueli Ma ◽  
...  
Keyword(s):  
Driving Force ◽  
Negative Capacitance ◽  
Thermodynamic Driving Force ◽  
Ferroelectric Capacitors

scholarly journals Thermodynamic Driving Forces and Chemical Reaction Fluxes; Reflections on the Steady State

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 699 ◽  
Author(s):  
Miloslav Pekař
Keyword(s):  
Steady State ◽  
Chemical Reaction ◽  
Driving Force ◽  
Driving Forces ◽  
Point Of View ◽  
Fluid Mixtures ◽  
Similar Work ◽  
Chemical Potentials ◽  
Thermodynamic Driving Force ◽  
Reacting Systems

Molar balances of continuous and batch reacting systems with a simple reaction are analyzed from the point of view of finding relationships between the thermodynamic driving force and the chemical reaction rate. Special attention is focused on the steady state, which has been the core subject of previous similar work. It is argued that such relationships should also contain, besides the thermodynamic driving force, a kinetic factor, and are of a specific form for a specific reacting system. More general analysis is provided by means of the non-equilibrium thermodynamics of linear fluid mixtures. Then, the driving force can be expressed either in the Gibbs energy (affinity) form or on the basis of chemical potentials. The relationships can be generally interpreted in terms of force, resistance and flux.

Interfacial Stability of CoSi2/Si Structures Grown by Molecular Beam Epitaxy

1991 ◽  
Vol 237 ◽  
Author(s):  
T. George ◽  
R. W. Fathauer
Keyword(s):  
Molecular Beam Epitaxy ◽  
Driving Force ◽  
Molecular Beam ◽  
Ostwald Ripening ◽  
Flux Ratio ◽  
Interfacial Stability ◽  
Capping Layer ◽  
Si Substrates ◽  
Interfacial Strain ◽  
The Stability

ABSTRACTThe stability of CoSi2/Si interfaces was examined in this study using columnar suicide structures grown on (111) Si substrates. In the first set of experiments, Co and Si were co-deposited (1:7 flux ratio) using molecular beam epitaxy at 800°C and the resulting columnar suicide layer was capped by epitaxial Si. Deposition of Co on the surface of the Si capping layer at 800°C results in the growth of the buried suicide columns. The buried columns grow by subsurface diffusion of the deposited Co, suppressing the formation of surface islands of CoSi2. The columns' sidewalls appear to be less stable than the top and bottom interfaces, resulting in preferential lateral growth and ultimately in the coalescence of the columns to form a continuous buried CoSi2 layer.In the second set of experiments, annealing of a 250nm-thick buried columnar layer at 1000°C under a 100nm-thick Si capping layer results in the formation of a surface layer of CoSi2 with a reduction in the sizes of the CoSi2 columns. For a sample having a thicker (500nm) Si capping layer the annealing leads to Ostwald ripening producing buried equiaxed columns. The' high CoSi2/Si interfacial strain could provide the driving force for the observed behavior of the buried columns under high-temperature annealing.

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