Kinetics of Intermetallic Formation in Free Standing Cu/Mg Multilayer Thin Films

1992 ◽  
Vol 260 ◽  
Author(s):  
B. Arcof ◽  
L. A. Clevenger ◽  
S. P. Murarka ◽  
J. M. E. Harper ◽  
C. Cabrai
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Layer Thickness ◽  
Reaction Times ◽  
Thickness Ratio ◽  
Formation Mechanisms ◽  
Multilayer Thin Films ◽  
Scanning Calorimetry ◽  
Free Standing ◽  
Layer Thickness Ratio

ABSTRACTDifferential scanning calorimetry (DSC) has been used to study the temperatures, kinetics and phase formation mechanisms in Cu/Mg multilayer thin films. When the Cu:Mg layer thickness ratio was 1:4, CuMg2 was the only phase that formed. Cu/Mg films with a layer thickness ratio of 1:1 first form CuMg2 at 215°C with an activation energy of 1.0 ± 0.04 eV and then Cu2Mg at 380°C with an activation energy of 0.73 ± 0.04 eV. The temperatures at which the two phases form decrease as the layer thicknesses decrease due to the shorter reaction times needed in thinner films. The constant scan rate DSC data from films with a layer thickness ratio of 1:1 show three exothermic peaks. The first peak is extremely sharp and results from the formation of isolated nuclei of CuMg2 at the Cu/Mg interface. The formation of CuMg2 is thus shown to be nucleation controlled. The second peak is a growth peak due to the heat released during the growth of CuMg2. The third peak corresponds to the formation and growth of Cu2Mg.

Tuning Negative Capacitance in PbZr0.2Ti0.8O3/SrTiO3 Heterostructures via Layer Thickness Ratio

2021 ◽  
Vol 16 (3) ◽  
Author(s):  
Yifei Hao ◽  
Tianlin Li ◽  
Yu Yun ◽  
Xin Li ◽  
Xuegang Chen ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Thickness Ratio ◽  
Negative Capacitance ◽  
Layer Thickness Ratio

Influence of Layer-Thickness Ratio on Magnetic Properties in F-La2/3Ca1/3MnO3/AF-La1/3Ca2/3MnO3 Bilayers

2012 ◽  
Vol 25 (7) ◽  
pp. 2193-2198 ◽  
Author(s):  
P. Prieto ◽  
L. Marín ◽  
S. M. Diez ◽  
J.-G. Ramirez ◽  
M. E. Gómez
Keyword(s):  
Magnetic Properties ◽  
Layer Thickness ◽  
Thickness Ratio ◽  
Layer Thickness Ratio

Experimental Study of Wave Loading by Internal Solitary Waves on a Submerged Slender Body

2020 ◽  
Author(s):  
Meng Ji ◽  
Ke Chen ◽  
Yunxiang You ◽  
Ruirui Zhang
Keyword(s):  
Layer Thickness ◽  
Solitary Waves ◽  
Wave Amplitude ◽  
Prediction Method ◽  
Thickness Ratio ◽  
Experimental Results ◽  
Slender Body ◽  
Internal Solitary Waves ◽  
Wave Loads ◽  
Layer Thickness Ratio

Abstract Although ocean structures are complex, they all can be disassembled into a number of simple-shaped parts. One common shape is the slender body mentioned in this paper, and we focus on studying the mechanism of this shape. Experiments were carried out to study features of wave loads exerted by internal solitary waves (ISWs) on a submerged slender body. ISWs were generated by a piston-type wave maker in a large-type density stratified two-layer fluid wave flume. Using a three-component force transducer, the force variation of three degree of freedom (DOF) on the model was recorded. A satisfactory prediction method is established for ISWs on a submerged slender body based on internal solitary wave theory, Morison equation and pressure integral. Calculations based on this new prediction method are in good agreement with the experimental results. The experimental results and calculations show that, different incident angles, wave amplitude and layer thickness ratio have great effects on the wave loads, especially transverse incident waves bring much more severely influence. Besides the forces increase linearly with the wave amplitude becoming larger, and the maximums of the horizontal forces increase with the layer thickness ratio increasing.

Tensile Tests of Low Density Multilayer Thin Films

1995 ◽  
Vol 403 ◽  
Author(s):  
D. van Heerden ◽  
D. Josell ◽  
D. Shechtman
Keyword(s):  
Thin Films ◽  
Tensile Tests ◽  
Low Density ◽  
Multilayer Thin Films ◽  
Free Standing ◽  
Aerospace Applications ◽  
Transmission Electron ◽  
Film Hardness ◽  
Potential Use ◽  
Mechanical Studies

AbstractAlthough mechanical studies of multilayer thin films are increasingly more abundant, the majority of studies merely determine film hardness using micro- or nanoindentation techniques. Actual tensile tests are still quite rare. We have therefore conducted tensile tests of free standing aluminum-titanium multilayer thin films. This system was selected for its potential use as a low density (3.3 g/cm3) structural material with potential aerospace applications. The strongest multilayers produced, with bilayer thicknesses 7nm Ti/16 nm Al, fractured at tensile stresses (UTS) of 900 MPa - well beyond the UTS of either of the constituent materials. Specimen characterization by xray diffraction as well as transmission electron microscopy (TEM) revealed near perfect texturing and an intriguing hcp to fec transformation of the titanium layers during preparation of samples for TEM viewing.

Numerical Investigation for Fracture Saturation in Multilayer Sedimentary Rock in Unsymmetrical Case

2013 ◽  
Vol 690-693 ◽  
pp. 3050-3053
Author(s):  
Feng Shan Han ◽  
Li Song
Keyword(s):  
Numerical Simulation ◽  
Layer Thickness ◽  
Sedimentary Rock ◽  
Process Analysis ◽  
Failure Process ◽  
Bottom Layer ◽  
Thickness Ratio ◽  
Fracture Spacing ◽  
Layer Thickness Ratio ◽  
Rock Failure Process

Opening mode fractures in multilayer sedimentary rock often are periodically distributed with fracture spacing scaled to the thickness of the fractured layer. In this paper, based on Rock Failure Process Analysis Code RFPA2D, a three layer model with a central layer and with the different thickness top and bottom layer, progressive formation in multilayer sedimentary rock at fracture saturation in unsymmetrical case is simulated. We investigate the change of the critical fracture spacing to layer thickness ratio as a function of the thickness of the top layer where the bottom layers is much thicker (5 times) than the fractured layer called the unsymmetrical case, in this unsymmetrical case, fracture saturation is simulated. By numerical simulation of RFPA2D, the critical spacing to layer thickness ratio decreases and tend to the same constant value as the thickness of the top layer increases. Numerical simulation shown that for the unsymmetrical case, if the adjacent layers are thicker than 1.5 times the thickness of the fractured layer, the multilayer sedimentary rock can be treated approximately as a system with infinitely thick top and bottom layers at fracture saturation.That should be useful in the design of engineering systems and in the prediction of fracture spacing in hydrocarbon reservoirs and groundwater aquifers.

Nucleation and Growth of the First Phase in Sputter-Deposited Nb/Al Multilayer Thin Films

1995 ◽  
Vol 398 ◽  
Author(s):  
K. Barmak ◽  
S. Vivekanand ◽  
F. Ma ◽  
C. Michaelsen
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Nucleation And Growth ◽  
Grain Structure ◽  
Multilayer Thin Films ◽  
Product Phase ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Sputter Deposited

ABSTRACTThe formation of the first phase in the reaction of sputter-deposited Nb/Al multilayer thin films has been studied by power-compensated and heat-flux differential scanning calorimetry, x-ray diffraction and transmission electron microscopy. The modulation periods of the films are in the range of 10-500 nm. Both types of calorimetrie measurements, performed at a constant heating rate, show the presence of two peaks (A and B) for the formation of the single product phase, NbAl3. Isothermal calorimetrie scans show that peak A is associated with a nucleation and growth type transformation. The formation of NbAl3 is thus interpreted as a two-stage process of nucleation and lateral growth to coalescence (peak A) followed by normal growth until the consumption of one or both reactants (peak B). Transmission electron microscopy investigations of samples annealed into the first stage of NbAl3 formation show the presence of this phase at the Nb/Al interface and its preferential growth along the grain boundaries of the Al layer. The latter highlights the role of reactant phase grain structure in product phase formation.

Sign in / Sign up

Export Citation Format

Share Document