Micro/Meso Roll-to-Plate (R2P) Imprinting Process to Fabricate Micro Channel/Riblet Features

2012 ◽  
Vol 271-272 ◽  
pp. 611-616
Author(s):  
Zhao Yang Gao ◽  
Lin Fa Peng ◽  
Pei Yun Yi ◽  
Xin Min Lai
Keyword(s):  
Grain Size ◽  
Low Cost ◽  
Pure Copper ◽  
Metallic Surface ◽  
Fabrication Technique ◽  
Low Emission ◽  
Micro Channels ◽  
Process System ◽  
Mould Cavity ◽  
Flexible Fabrication

Functional metallic surface micro/meso structures such as micro channels/grooves or micro riblets have been increasingly applied in many fields, such as optics, tribology, fluid-dynamics and heat exchange or mass tranfer. Micro/meso forming has the potential of efficiently and economically fabricating functional microstructures over a large surface area. A mciro/meso roll-to-plate imprinting technique was proposed and the process system was self-developed. The pure copper specimens with various grains were imprinted to investigate the effects of mould cavity dimensions (width, spacing, and fillet) and grain size on the formation of features. It was concluded that the width and grain size had significant effects on the feature formation. Wider groove or larger size grain was helpful to enhance the flowability of materials. Moreover, the technique was validated for high throughput, low cost, low emission, and flexible fabrication technique.

scholarly journals Experimental and Numerical Investigation of the ECAP Processed Copper: Microstructural Evolution, Crystallographic Texture and Hardness Homogeneity

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 607
Author(s):  
A. I. Alateyah ◽  
Mohamed M. Z. Ahmed ◽  
Yasser Zedan ◽  
H. Abd El-Hafez ◽  
Majed O. Alawad ◽  
...  
Keyword(s):  
Grain Size ◽  
Equal Channel Angular Pressing ◽  
Cross Section ◽  
Room Temperature ◽  
Pure Copper ◽  
High Density ◽  
Ecap Processing ◽  
Heterogeneous Distribution ◽  
Angular Pressing ◽  
Average Grain Size

The current study presents a detailed investigation for the equal channel angular pressing of pure copper through two regimes. The first was equal channel angular pressing (ECAP) processing at room temperature and the second was ECAP processing at 200 °C for up to 4-passes of route Bc. The grain structure and texture was investigated using electron back scattering diffraction (EBSD) across the whole sample cross-section and also the hardness and the tensile properties. The microstructure obtained after 1-pass at room temperature revealed finer equiaxed grains of about 3.89 µm down to submicrons with a high density of twin compared to the starting material. Additionally, a notable increase in the low angle grain boundaries (LAGBs) density was observed. This microstructure was found to be homogenous through the sample cross section. Further straining up to 2-passes showed a significant reduction of the average grain size to 2.97 µm with observable heterogeneous distribution of grains size. On the other hand, increasing the strain up to 4-passes enhanced the homogeneity of grain size distribution. The texture after 4-passes resembled the simple shear texture with about 7 times random. Conducting the ECAP processing at 200 °C resulted in a severely deformed microstructure with the highest fraction of submicron grains and high density of substructures was also observed. ECAP processing through 4-passes at room temperature experienced a significant increase in both hardness and tensile strength up to 180% and 124%, respectively.

Reactive Milling and Mechanical Alloying in Electroceramics

2010 ◽  
Vol 63 ◽  
pp. 420-424
Author(s):  
Riva Rivas-Marquez ◽  
Carlos Gomez-Yanez ◽  
Ivan Velasco-Davalos ◽  
Jesus Cruz-Rivera
Keyword(s):  
Grain Size ◽  
Mechanical Activation ◽  
Raw Materials ◽  
Planetary Mill ◽  
Fabrication Technique ◽  
Nonlinearity Coefficient ◽  
Grain Sizes ◽  
Zno Varistor ◽  
Reactive Milling ◽  
Good Homogeneity

Using Mechanical Activation it is possible to obtain small grain size and good homogeneity in a ceramic piece. For ZnO varistor devices Mechanical Activation appears to be a good fabrication technique, since good homogeneity and small grain sizes are advantageous microstructural features. The typical formulation is composed by ZnO, Bi2O3, Sb2O3, CoO, MnO2 and Cr2O3 as raw materials, and during sintering, several dissolutions and reactions to form pyrochlore and spinel phases occur. When Mechanical Activation is applied to the entire formulation, it is difficult to know what processes are being mechanically activated due to the complexity of the system. The aim of the present work was to clarify how the mechanical activation is taking place in a typical ZnO varistor formulation. The methodology consisted in the formation of all possible combinations of two out of the five oxides above mentioned and to apply mechanical activation on the mixture of each pair of powders. The results showed that systems containing Bi2O3 are prone to react during mechanical activation. Also, reduction reactions were observed in MnO2. In addition, the powder mixture corresponding to the whole formulation was milled in a planetary mill, pressed and sintered, and varistor devices were fabricated. Improvement in the nonlinearity coefficient and breakdown voltage was observed.

A High Effective and Low-Cost Modifier for Hypereutectic Al-Si Alloys

2013 ◽  
Vol 721 ◽  
pp. 282-286
Author(s):  
Guang Hui Qi
Keyword(s):  
Grain Size ◽  
Master Alloy ◽  
Low Cost ◽  
Environment Pollution ◽  
Casting Method ◽  
Good Future ◽  
Primary Si ◽  
Average Grain Size ◽  
Master Alloys

In order to settle environment pollution and provide a high effective and low-cost modifier for refining the primary Si in hypereutectic Al-Si alloys, Al-Fe-P master alloys containing 2.0~5.0% phosphorus have been invented by casting method. The Al-Fe-P master alloys can be conveniently produced and an excellent modification can be obtained by adding 0.3~0.8wt% Al-Fe-P master alloy in Al-Si alloys containing 12%-25% Si at a relatively lower modifying temperature. The number of primary Si increases obviously and the average grain size of primary Si decreases largely, less than 50μm. Furthermore Al-Fe-P master alloys have many advantages, such as low cost, convenient operation technology, no pollution, stable and long-term modification effect, easy storage and etc. Al-Fe-P master alloys have overcome the shortages of current modifier and have a good future for hypereutectic Al-Si alloy modification.

scholarly journals Spatially resolved measurements of grain size effects on the shock and spall response of quasi-Taylor wave loaded pure copper

2017 ◽  
Vol 122 (3) ◽  
pp. 035106
Author(s):  
G. Whiteman ◽  
G. D. Owen ◽  
J. De'Ath ◽  
D. J. Chapman ◽  
D. E. Eakins ◽  
...  
Keyword(s):  
Grain Size ◽  
Size Effects ◽  
Pure Copper ◽  
Spatially Resolved ◽  
Grain Size Effects

scholarly journals Optimization of a Handwriting Method by an Automated Ink Pen for Cost-Effective and Sustainable Sensors

Chemosensors ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 264
Author(s):  
Florin C. Loghin ◽  
José F. Salmerón ◽  
Paolo Lugli ◽  
Markus Becherer ◽  
Aniello Falco ◽  
...  
Keyword(s):  
Printed Electronics ◽  
Low Cost ◽  
Electronic Devices ◽  
Cost Effective ◽  
Capacitive Sensor ◽  
Fabrication Technique ◽  
Rfid Tag ◽  
Environmental Friendly ◽  
Fast Prototyping ◽  
Do It Yourself

In this work, we present a do-it-yourself (DIY) approach for the environmental-friendly fabrication of printed electronic devices and sensors. The setup consists only of an automated handwriting robot and pens filled with silver conductive inks. Here, we thoroughly studied the fabrication technique and different optimized parameters. The best-achieved results were 300 mΩ/sq as sheet resistance with a printing resolution of 200 µm. The optimized parameters were used to manufacture fully functional electronics devices: a capacitive sensor and a RFID tag, essential for the remote reading of the measurements. This technique for printed electronics represents an alternative for fast-prototyping and ultra-low-cost fabrication because of both the cheap equipment required and the minimal waste of materials, which is especially interesting for the development of cost-effective sensors.

scholarly journals Size Effect on Mechanical Properties and Deformation Behavior of Pure Copper Wires Considering Free Surface Grains

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4563
Author(s):  
Yu Hou ◽  
Xujun Mi ◽  
Haofeng Xie ◽  
Wenjing Zhang ◽  
Guojie Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Free Surface ◽  
Size Effect ◽  
Single Crystal ◽  
Deformation Behavior ◽  
Pure Copper ◽  
Critical Value ◽  
Wire Diameter ◽  
Surface Model

The size (grain size and specimen size) effect makes traditional macroscopic forming technology unsuitable for a microscopic forming process. In order to investigate the size effect on mechanical properties and deformation behavior, pure copper wires (diameters range from 50 μm to 500 μm) were annealed at different temperatures to obtain different grain sizes. The results show that a decrease in wire diameter leads to a reduction in tensile strength, and this change is pronounced for large grains. The elongation of the material is in linear correlation to size factor D/d (diameter/grain size), i.e., at the same wire diameter, more grains in the section bring better plasticity. This phenomenon is in relationship with the ratio of free surface grains. A surface model combined with the theory of single crystal and polycrystal is established, based on the relationship between specimen/grain size and tensile property. The simulated results show that the flow stress in micro-scale is in the middle of the single crystal model (lower critical value) and the polycrystalline model (upper critical value). Moreover, the simulation results of the hybrid model calculations presented in this paper are in good agreement with the experimental results.

scholarly journals Feasibility Study for a Chemical Process Particle Size Characterization System for Explosive Environments Using Low Laser Power

Micromachines ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 911
Author(s):  
Jesse Ross-Jones ◽  
Tobias Teumer ◽  
Susann Wunsch ◽  
Lukas Petri ◽  
Hermann Nirschl ◽  
...  
Keyword(s):  
Light Scattering ◽  
Low Cost ◽  
Particle Diameter ◽  
Feasibility Studies ◽  
Fast Response ◽  
The Novel ◽  
Micro Channels ◽  
Size Characterization ◽  
Novel Method ◽  
Particle Size Characterization

The industrial particle sensor market lacks simple, easy to use, low cost yet robust, safe and fast response solutions. Towards development of such a sensor, for in-line use in micro channels under continuous flow conditions, this work introduces static light scattering (SLS) determination of particle diameter using a laser with an emission power of less than 5 µW together with sensitive detectors with detection times of 1 ms. The measurements for the feasibility studies are made in an angular range between 20° and 160° in 2° increments. We focus on the range between 300 and 1000 nm, for applications in the production of paints, colors, pigments and crystallites. Due to the fast response time, reaction characteristics in microchannel designs for precipitation and crystallization processes can be studied. A novel method for particle diameter characterization is developed using the positions of maxima and minima and slope distribution. The novel algorithm to classify particle diameter is especially developed to be independent of dispersed phase concentration or concentration fluctuations like product flares or signal instability. Measurement signals are post processed and particle diameters are validated against Mie light scattering simulations. The design of a low cost instrument for industrial use is proposed.

scholarly journals Effect of Solution Conditions on the Properties of Sol–Gel Derived Potassium Sodium Niobate Thin Films on Platinized Sapphire Substrates

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1600 ◽  
Author(s):  
Alexander Tkach ◽  
André Santos ◽  
Sebastian Zlotnik ◽  
Ricardo Serrazina ◽  
Olena Okhay ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Low Cost ◽  
Sol Gel ◽  
Precursor Solution ◽  
Dissipation Factor ◽  
Solution Concentration ◽  
Potassium Sodium Niobate ◽  
Sapphire Substrates ◽  
Average Grain Size

If piezoelectric micro-devices based on K0.5Na0.5NbO3 (KNN) thin films are to achieve commercialization, it is critical to optimize the films’ performance using low-cost scalable processing conditions. Here, sol–gel derived KNN thin films are deposited using 0.2 and 0.4 M precursor solutions with 5% solely potassium excess and 20% alkali (both potassium and sodium) excess on platinized sapphire substrates with reduced thermal expansion mismatch in relation to KNN. Being then rapid thermal annealed at 750 °C for 5 min, the films revealed an identical thickness of ~340 nm but different properties. An average grain size of ~100 nm and nearly stoichiometric KNN films are obtained when using 5% potassium excess solution, while 20% alkali excess solutions give the grain size of 500–600 nm and (Na + K)/Nb ratio of 1.07–1.08 in the prepared films. Moreover, the 5% potassium excess solution films have a perovskite structure without clear preferential orientation, whereas a (100) texture appears for 20% alkali excess solutions, being particularly strong for the 0.4 M solution concentration. As a result of the grain size and (100) texturing competition, the highest room-temperature dielectric permittivity and lowest dissipation factor measured in the parallel-plate-capacitor geometry were obtained for KNN films using 0.2 M precursor solutions with 20% alkali excess. These films were also shown to possess more quadratic-like and less coercive local piezoelectric loops, compared to those from 5% potassium excess solution. Furthermore, KNN films with large (100)-textured grains prepared from 0.4 M precursor solution with 20% alkali excess were found to possess superior local piezoresponse attributed to multiscale domain microstructures.

The Effects of Free Space in Mould Cavity on Sandglass Extrusion

2005 ◽  
Vol 475-479 ◽  
pp. 2999-3002
Author(s):  
W.L. Lu ◽  
Y. Wang ◽  
Jin Tao Hai
Keyword(s):  
Grain Size ◽  
Free Space ◽  
Large Strain ◽  
Experimental Results ◽  
Experimental Result ◽  
Ultrafine Grain ◽  
Theory Analysis ◽  
Ultrafine Grain Size ◽  
Mould Cavity

Sandglass extrusion is an ultrafine grain size method. Due to the repetitive and multiple extrusions, large strain will be accumulated and ultafine grain size can be obtained. There are some factors that can affect the experimental result of sandglass extrusion. Among these factors, free space in mould cavity is very important, which can affect the forming of the fold during the extrusion. In this paper, the effects of free space in mould cavity on sandglass extrusion have been discussed and theory analysis and experimental results have been reported.

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