Hardening Mechanisms of Amorphous / Polycrystalline Nanostructured Multilayer Films: Si3N4/CrN and Si3N4/TiN

2002 ◽  
Vol 750 ◽  
Author(s):  
Junhua Xu ◽  
Lihua Yu ◽  
Yasushi Azuma ◽  
Koichiro Hattori ◽  
Toshiyuki Fujimoto ◽  
...  
Keyword(s):  
Substrate Temperature ◽  
Layer Thickness ◽  
Deposition Temperature ◽  
Multilayer Films ◽  
Thickness Ratio ◽  
Reactive Magnetron ◽  
Maximum Hardness ◽  
Layer Thickness Ratio ◽  
Hardening Mechanisms ◽  
Hardness Values

ABSTRACTThe amorphous/polycrystalline Si3N4/CrN and Si3N4/TiN nano-structured multilayer films have been fabricated by RF reactive magnetron sputtering. The microstructure and properties of these films were measured by XRD, HRTEM and nano-indenter There is no superhardness effect in the Si3N4/CrN multilayers. The hardness values of Si3N4/CrN multilayers are between those of the constituent CrN and Si3N4 films at a substrate temperature of 20∼C, and are a little higher than those of Si3N4 films at a deposition temperature of 500°C. However, the superhardness effect was found in Si3N4/ TiN multilayers. The hardness of Si3N4/ TiN multilayers is affected not only by modulation periods, but also by layer thickness ratio and deposition temperature. The maximum hardness value is about 40% higher than the value calculated from the rule of mixtures at a deposition temperature of 500°C and a layer thickness ratio (lSi3N4/ lTiN) of 3 / 1. Based on experimental results, the hardening mechanisms in these multilayers have been discussed.

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

Modulation Structure and Superhardness Effect of VC/TiN Nano-Multilayer Films

2012 ◽  
Vol 184-185 ◽  
pp. 1080-1083
Author(s):  
Jian Ling Yue ◽  
Wei Shi ◽  
Ge Yang Li
Keyword(s):  
Elastic Modulus ◽  
Magnetron Sputtering ◽  
Layer Thickness ◽  
Coherent Structure ◽  
Multilayer Films ◽  
Critical Layer ◽  
Maximum Hardness ◽  
Critical Layer Thickness ◽  
The Relationship

A series of VC/TiN nano-multilayer films with various TiN layer thicknesses were synthesized by magnetron sputtering method. The relationship between the modulation structure and superhardness effect of the multilayer films were investigated. The results reveal that TiN below a critical layer thickness grows coherently with VC layers in multilayers. Correspondingly, the hardness and elastic modulus of the multilayers increase significantly. The maximum hardness and modulus achieved in these multilayers is 40.7GPa and 328GPa.With further increase in the TiN layer thickness, coherent structure of multilayers are destroyed, resulting in a remarkable decrease of hardness and modulus. The superhardness effect of multilayers is related to the three directional strains generated from the coherent structure.

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.

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.

Hygrothermal Effects on Dynamic Instability of Hybrid Composite Plates

2017 ◽  
Vol 17 (01) ◽  
pp. 1750001 ◽  
Author(s):  
Chun-Sheng Chen ◽  
An-Hung Tan ◽  
Jin-Yih Kao ◽  
Wei-Ren Chen
Keyword(s):  
Layer Thickness ◽  
Hybrid Composite ◽  
Volume Fraction ◽  
Dynamic Instability ◽  
Composite Plates ◽  
Thickness Ratio ◽  
Fiber Volume ◽  
Periodic Load ◽  
Moisture Concentration ◽  
Layer Thickness Ratio

The dynamic characteristics of hybrid composite plates under an arbitrary periodic load in hygrothermal environments are investigated. The material properties of the plate are assumed to be dependent on the temperature and moisture. The governing equations of motion of the Mathieu-type are established based on the Galerkin method with reduced eigenfunction transforms. The periodic stress is taken to be a combination of the pulsating axial and bending stress in the example problems. Based on Bolotin’s method, the dynamic instability behaviors of hybrid composite plates are determined. The effects of layer thickness ratio, fiber volume fraction, temperature rise, moisture concentration and dynamic load on the instability regions of hybrid composite plates are studied, along with the dynamic instability index discussed. The results reveal that the layer thickness ratio and hygrothermal conditions have a significant impact on the dynamic instability of hybrid composite plates.

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