scholarly journals Direct Generation of High-Aspect-Ratio Structures of AISI 316L by Laser-Assisted Powder Deposition

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5670
Author(s):  
Piera Alvarez ◽  
M. Ángeles Montealegre ◽  
Francisco Cordovilla ◽  
Ángel García-Beltrán ◽  
Ignacio Angulo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aspect Ratio ◽  
Cross Sections ◽  
High Aspect Ratio ◽  
316L Stainless Steel ◽  
Laser Metal Deposition ◽  
Homogeneous Microstructure ◽  
Tension Tests ◽  
Powder Deposition ◽  
Direct Generation

The effect of process parameters and the orientation of the cladding layer on the mechanical properties of 316L stainless steel components manufactured by laser metal deposition (LMD) was investigated. High aspect-ratio walls were manufactured with layers of a 4.5 mm wide single-cladding track to study the microstructure and mechanical properties along the length and the height of the wall. Samples for the tensile test (according to ASTM E-8M-04) were machined from the wall along both the direction of the layers and the direction perpendicular to them. Cross-sections of the LMD samples were analyzed by optical and scanning electron microscopy (SEM). The orientation of the growing grain was observed. It was associated with the thermal gradient through the building part. A homogeneous microstructure between consecutive layers and some degree of microporosity was observed by SEM. Uniaxial tension tests were performed on samples extracted from the wall in perpendicular and parallel directions. Results for ultimate tensile strength were similar in both cases and with the wrought material. The σ0.2 were similar in both cases but slightly superior to the wrought material.

Wafer-Scale, Highly-Ordered Silicon Nanowires Produced by Step-and-Flash Imprint Lithography and Metal-Assisted Chemical Etching

2012 ◽  
Vol 1512 ◽  
Author(s):  
Jian-Wei Ho ◽  
Qixun Wee ◽  
Jarrett Dumond ◽  
Li Zhang ◽  
Keyan Zang ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Cross Sections ◽  
Silicon Nanowires ◽  
High Aspect Ratio ◽  
Chemical Etching ◽  
Semiconductor Device ◽  
Imprint Lithography ◽  
Wafer Level ◽  
Conventional Photolithography ◽  
Metal Assisted Chemical Etching

ABSTRACTA combinatory approach of Step-and-Flash Imprint Lithography (SFIL) and Metal-Assisted Chemical Etching (MacEtch) was used to generate near perfectly-ordered, high aspect ratio silicon nanowires (SiNWs) on 4" silicon wafers. The ordering and shapes of SiNWs depends only on the SFIL nanoimprinting mould used, thereby enabling arbitary SiNW patterns not possible with nanosphere and interference lithography (IL) to be generated. Very densely packed SiNWs with periodicity finer than that permitted by conventional photolithography can be produced. The height of SiNWs is, in turn, controlled by the etching duration. However, it was found that very high aspect ratio SiNWs tend to be bent during processing. Hexagonal arrays of SiNW with circular and hexagonal cross-sections of dimensions 200nm and less were produced using pillar and pore patterned SFIL moulds. In summary, this approach allows highlyordered SiNWs to be fabricated on a wafer-level basis suitable for semiconductor device manufacturing.

Functionalization and Tip-open of Carbon Nanotubes for High-Performance Symmetric Supercapacitor

2021 ◽  
Author(s):  
Yaxiong Zhang ◽  
Erqing Xie
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Aspect Ratio ◽  
Specific Surface ◽  
Surface Area ◽  
Chemical Stability ◽  
High Aspect Ratio ◽  
High Performance ◽  
Large Specific Surface Area ◽  
Symmetric Supercapacitor

Carbon nanotubes (CNTs) have been widely studied as supercapacitor electrodes because of their excellent conductivity, high aspect ratio, excellent mechanical properties, chemical stability, and large specific surface area. However, the...

scholarly journals Strain and Temperature Sensitivities Along with Mechanical Properties of CNT Buckypaper Sensors

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3067
Author(s):  
Shiuh-Chuan Her ◽  
Wei-Chun Hsu
Keyword(s):  
Mechanical Properties ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Complex Surface ◽  
Thermogravimetric Analyzer ◽  
Low Aspect Ratio ◽  
Four Point Bending ◽  
Thermal Chamber ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

In this work, buckypaper composed of multi-walled carbon nanotubes (MWCNT) was prepared through a vacuum filtration process. The effect of MWCNT aspect ratio on the buckypaper performance was investigated. The freestanding and highly flexible buckypaper can be used as a sensor to attach on a complex surface monitoring the strain and temperature at the critical area. The mechanical properties of the buckypaper were examined using the tensile and nanoindentation tests. The strain and temperature sensitivities of the buckypaper were evaluated through the four-point bending and thermal chamber tests, respectively. In addition, the microstructure and thermal stability of the buckypaper were studied by scanning electron microscopy (SEM) and thermogravimetric analyzer (TGA), respectively. Experimental results showed that the mechanical properties such as Young’s modulus, tensile strength, fracture strain, and hardness of the buckypaper made of high aspect ratio MWCNTs were significantly superior to the buckypaper consisted of low aspect ratio MWCNTs, while the strain and temperature sensitivities of the buckypaper composed of low aspect ratio MWCNTs were better than that of the buckypaper made of high aspect ratio MWCNTs.

Mechanical Property Evaluation of Electroplated High Aspect Ratio Microstructures

1998 ◽  
Vol 518 ◽  
Author(s):  
L. S. Stephens ◽  
K.W. Kelly ◽  
E.I. Meletis ◽  
S. Simhadri
Keyword(s):  
Mechanical Properties ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Mold Insert ◽  
Processing Parameters ◽  
Strength Properties ◽  
Knoop Hardness ◽  
Modulus Of Rupture ◽  
Mechanical Seal ◽  
Property Evaluation

AbstractHigh aspect ratio microstructures (HARMs) with a height of hundreds of micrometers and a width of a few tens of micrometers present high promise in a number of challenging fields. At LSU, a number of applications are being developed in which nickel HARMs are electroplated on metal surfaces (mold insert fabrication for the LIGA process, HARMs on mechanical seal faces, HARMs on heat exchange surfaces, etc.). In some of these applications, the HARMs are subjected to high stresses and the mechanical properties are particularly important. These properties can be used to adjust processing parameters to optimize properties of the HARMS.This paper presents a method for measuring the strength properties of cantilevered nickel HARMs constructed by LIGA. Experimentally measured values are reported for modulus of rupture (1280 MPa), Young's modulus (153 GPa) and Knoop hardness (500 Hk) for HARMs with an overplated base. SEM micrographs clearly indicate that failure of the beams is brittle and most frequently occurs at the interface of the beam and overplated base.

Mechanical properties of natural rubber nanocomposites reinforced with high aspect ratio cellulose nanocrystals isolated from soy hulls

2016 ◽  
Vol 153 ◽  
pp. 143-152 ◽  
Author(s):  
Wilson Pires Flauzino Neto ◽  
Marcos Mariano ◽  
Ingrid Souza Vieira da Silva ◽  
Hudson Alves Silvério ◽  
Jean-Luc Putaux ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aspect Ratio ◽  
Natural Rubber ◽  
Cellulose Nanocrystals ◽  
High Aspect Ratio ◽  
Soy Hulls ◽  
Rubber Nanocomposites

scholarly journals Mechanically Improved and Multifunctional CFRP Enabled by Resins with High Concentrations Epoxy-Functionalized Fluorographene Fillers

2021 ◽  
Author(s):  
Junhua Wei
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Elastic Modulus ◽  
Carbon Fiber ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Reinforcing Particles ◽  
Thermoset Resin ◽  
High Concentrations ◽  
Carbon Based

To meet the maximum potential of the mechanical properties of carbon fiber reinforced plastics (CFRP), stress transfer between the carbon fibers through the polymer matrix must be improved. A recent promising approach reportedly used reinforcing particles as fillers dispersed in the resin. Carbon based fillers are an excellent candidate for such reinforcing particles due to their intrinsically high mechanical properties, structure and chemical nature similar to carbon fiber and high aspect ratio. They have shown great potential in increasing the strength, elastic modulus and other mechanical properties of interest of CFRPs. However, a percolation threshold of ~1% of the carbon-based particle concentration in the base resin has generally been reported, beyond which the mechanical properties deteriorate due to particle agglomeration. As a result, the potential for further increase of the mechanical properties of CFRPs with carbon-based fillers is limited. We report a significant increase in the strength and elastic modulus of CFRPs, achieved with a novel reinforced thermoset resin that contains high loadings of epoxy-reacted fluorographene (ERFG) fillers. We found that the improvement in mechanical performance of CFRPs was correlated with increase in ERFG loading in the resin. Using a novel thermoset resin containing 10 wt% ERFG filler, CFRPs fabricated by wet layup technique with twill weaves showed a 19.6% and 17.7% increase in the elastic modulus and tensile strength respectively. In addition, because of graphene’s high thermal conductivity and high aspect ratio, the novel resin enhanced CFRPs possessed 59.3% higher through-plane thermal conductivity and an 81-fold reduction in the hydrogen permeability. The results of this study demonstrate that high loadings of functionalized particles dispersed in the resin is a viable path towards fabrication of improved, high-performance CFRP parts and systems.

Statistical Analysis of Tensile Tests Performed on 316L Specimens Manufactured by Directed Energy Deposition

2020 ◽  
Author(s):  
A. P. Iliopoulos ◽  
J. P. Thomas ◽  
J. C. Steuben ◽  
R. Saunders ◽  
J. G. Michopoulos ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Statistical Analysis ◽  
Energy Deposition ◽  
316L Stainless Steel ◽  
Failure Strain ◽  
Bulk Material ◽  
Tensile Tests ◽  
Tension Tests ◽  
Directed Energy ◽  
Manufacturing Parameters

Abstract The present work reports on the results of tension tests conducted on 316L stainless steel specimens extracted out of thin-walled boxes produced by powder jet additive manufacturing. The specimens were minimally processed to study the potential effects of the manufacturing process on the apparent mechanical properties rather than identifying the properties of the resulting bulk material. Statistical analysis is performed and presented in an attempt to identify correlations between the manufacturing parameters and the apparent mechanical properties. The mechanical properties of interest are Young’s modulus, the yield stress (measured at the 0.2% level), the ultimate stress, and the failure strain.

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