scholarly journals Effect of Alloying Type and Lean Sintering Atmosphere on the Performance of PM Components

2017 ◽  
Vol 17 (2) ◽  
pp. 72-81
Author(s):  
M. Vattur Sundaram ◽  
R. Shvab ◽  
S. Millot ◽  
E. Hryha ◽  
L. Nyborg
Keyword(s):  
Process Development ◽  
Cost Effective ◽  
Processing Route ◽  
Case Hardening ◽  
Structural Components ◽  
Sintering Atmosphere ◽  
Martensitic Microstructure ◽  
Metallurgy Steel ◽  
Different Temperatures ◽  
And Diffusion

Abstract In order to be cost effective and to meet increasing performance demands, powder metallurgy steel components require continuous improvement in terms of materials and process development. This study demonstrates the feasibility of manufacturing structural components using two different alloys systems, i.e. lean Cr-prealloyed and diffusion bonded water atomised powders with different processing conditions. The components were sintered at two different temperatures, i.e. 1120 and 1250 °C for 30 minutes in three different atmospheres: vacuum, N2- 10%H2 atmosphere as well as lean N2-5%H2-0.5%CO-(0.1-0.4)%CH4 sintering atmosphere. Components after sintering were further processed by either low pressure carburizing, sinterhardening or case hardening. All trials were performed in the industrial furnaces to simulate the actual production of the components. Microstructure, fractography, apparent and micro hardness analyses were performed close to the surface and in the middle of the sample to characterize the degree of sintering (temperature and atmosphere) and the effect of heat treatment. In all cases, components possess mostly martensitic microstructure with a few bainitic regions. The fracture surface shows well developed sinter necks. Inter- and trans-granular ductile and cleavage fracture modes are dominant and their fraction is determined by the alloy and processing route.

scholarly journals Development of Quantum Dot (QD) Based Color Converters for Multicolor Display

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1089
Author(s):  
Muhammad T. Sajjad ◽  
Ashu K. Bansal ◽  
Francesco Antolini ◽  
Eduard Preis ◽  
Lenuta Stroea ◽  
...  
Keyword(s):  
Polymer Matrix ◽  
Cost Effective ◽  
Final Size ◽  
Force Microscopy ◽  
Morphological Studies ◽  
Color Displays ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Color Conversion ◽  
Temperature Time

Many displays involve the use of color conversion layers. QDs are attractive candidates as color converters because of their easy processability, tuneable optical properties, high photoluminescence quantum yield, and good stability. Here, we show that emissive QDs with narrow emission range can be made in-situ in a polymer matrix, with properties useful for color conversion. This was achieved by blending the blue-emitting pyridine based polymer with a cadmium selenide precursor and baking their films at different temperatures. To achieve efficient color conversion, blend ratio and baking temperature/time were varied. We found that thermal decomposition of the precursor leads to highly emissive QDs whose final size and emission can be controlled using baking temperature/time. The formation of the QDs inside the polymer matrix was confirmed through morphological studies using atomic force microscopy (AFM) and transmission electron microscopy (TEM). Hence, our approach provides a cost-effective route to making highly emissive color converters for multi-color displays.

Robustness versus Performance Assessment for Different Gamma-TiAl Processing Routes

2011 ◽  
Vol 1295 ◽  
Author(s):  
Marc Thomas
Keyword(s):  
High Performance ◽  
Cost Effective ◽  
Processing Route ◽  
Transportation Industry ◽  
Tial Alloys ◽  
Alternative Processing ◽  
Aerospace Applications ◽  
Robust Processing ◽  
Processing Techniques ◽  
Robust Process

ABSTRACTOne of the main driving force for the development of advanced structural materials is weight saving especially in the transportation industry in order to reduce CO2 emission. The utilization of gamma aluminides, as good candidates for aerospace applications, is strongly related to the development of a cost-effective and robust processing route, as far as possible. It is well established that the processing route, i.e. cast, wrought or PM, has a dramatic effect on the microstructure and texture of gamma-TiAl alloys. Therefore, significant microstructural variations through post-heat treatments coupled with compositional modifications can only guarantee a proper balance of desired properties. However, a number of metallurgical factors during the processing steps can contribute to some scattering in properties. This review will highlight several critical process variables in terms of the resulting g-TiAl microstructures. Of primary importance is the as-cast texture which is difficult to control and may contribute to prefer some alternative processing routes to ensure a better repeatability in mechanical results. Some innovative processing techniques for controlling the structure will then be presented. The main point which will be discussed in this paper is whether an approach leading to a robust process would not be at the expense of the high performance of the structural material.

scholarly journals Accelerated discovery of high-strength aluminum alloys by machine learning

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Jiaheng Li ◽  
Yingbo Zhang ◽  
Xinyu Cao ◽  
Qi Zeng ◽  
Ye Zhuang ◽  
...  
Keyword(s):  
Machine Learning ◽  
Aluminum Alloys ◽  
Mechanical Performance ◽  
High Strength ◽  
Cost Effective ◽  
Alloy System ◽  
Processing Route ◽  
Specific Strength ◽  
Cu Alloy ◽  
High Strength Aluminum Alloys

Abstract Aluminum alloys are attractive for a number of applications due to their high specific strength, and developing new compositions is a major goal in the structural materials community. Here, we investigate the Al-Zn-Mg-Cu alloy system (7xxx series) by machine learning-based composition and process optimization. The discovered optimized alloy is compositionally lean with a high ultimate tensile strength of 952 MPa and 6.3% elongation following a cost-effective processing route. We find that the Al8Cu4Y phase in wrought 7xxx-T6 alloys exists in the form of a nanoscale network structure along sub-grain boundaries besides the common irregular-shaped particles. Our study demonstrates the feasibility of using machine learning to search for 7xxx alloys with good mechanical performance.

scholarly journals Investigation of Fatigue Behavior of ABS and PC-ABS Polymers at Different Temperatures

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1818
Author(s):  
Andrea Mura ◽  
Alessando Ricci ◽  
Giancarlo Canavese
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Working Condition ◽  
Fatigue Behavior ◽  
Polymeric Materials ◽  
Cyclic Loads ◽  
Structural Components ◽  
Working Temperature ◽  
Different Temperatures ◽  
Positive Effect

Plastics are widely used in structural components where cyclic loads may cause fatigue failure. In particular, in some applications such as in vehicles, the working temperature may change and therefore the strength of the polymeric materials. In this work, the fatigue behavior of two thermoplastic materials (ABS and PC-ABS) at different temperatures has been investigated. In particular, three temperatures have been considered representing the working condition at room temperature, at low temperature (winter conditions), and high temperature (summer conditions and/or components close to the engine). Results show that high temperature have big impact on fatigue performance, while low temperatures may also have a slight positive effect.

An Experimental Study of Compatibility for Metallic Inserts Bonded into CFRP Laminates Soaked in Aircraft Fuel

2015 ◽  
Vol 1095 ◽  
pp. 518-522
Author(s):  
Xue Mei Chen ◽  
Jing Liu ◽  
Jing Xu ◽  
Hui Zhang ◽  
Feng Tao He ◽  
...  
Keyword(s):  
Cost Effective ◽  
Structural Components ◽  
Interference Fit ◽  
Cfrp Laminates ◽  
Aircraft Fuel ◽  
Mechanical And Physical Properties ◽  
Series Of Experiments ◽  
Breakaway Torque ◽  
Torque Values ◽  
Push Out

CFRP laminates are used for various aircraft structural components because of their good mechanical and physical properties. Metallic inserts are one kind of aerospace fasteners, which are usually installed in the metallic components by an interference fit. However, when metallic inserts are installed in the CFRP laminates by the traditional installing way, delamination and low efficiencies are troublesome. Therefore, excellent quality and cost effective installing metallic inserts into the CFRP laminates remains a challenge. In this paper, a series of experiments were carried out to study the compatibility for metallic inserts bonded into the CFRP laminates soaked in the aircraft fuel. The experimental results show that the push-out values and breakaway torque values of metallic inserts bonded in the CFRP laminates soaked in the fuel are not reduced compared with these values of sample was not prepared in that way.

Third generation of advanced high-strength steels: Processing routes and properties

2016 ◽  
Vol 233 (2) ◽  
pp. 209-238 ◽  
Author(s):  
Tarun Nanda ◽  
Vishal Singh ◽  
Virender Singh ◽  
Arnab Chakraborty ◽  
Sandeep Sharma
Keyword(s):  
Automobile Industry ◽  
Second Generation ◽  
Low Cost ◽  
High Strength Steels ◽  
High Strength ◽  
Cost Effective ◽  
Processing Route ◽  
Third Generation ◽  
Specific Strength ◽  
Advanced High Strength Steels

The automobile industry is presently focusing on processing of advanced steels with superior strength–ductility combination and lesser weight as compared to conventional high-strength steels. Advanced high-strength steels are a new class of materials to meet the need of high specific strength while maintaining the high formability required for processing, and that too at reasonably low cost. First and second generation of advanced high-strength steels suffered from some limitations. First generation had high strength but low formability while second generation possessed both strength and ductility but was not cost effective. Amongst the different types of advanced high-strength steels grades, dual-phase steels, transformation-induced plasticity steels, and complex phase steels are considered as very good options for being extended into third generation advanced high-strength steels. The present review presents the various processing routes for these grades developed and discussed by different authors. A novel processing route known as quenching and partitioning route is also discussed. The review also discusses the resulting microstructures and mechanical properties achieved under various processing conditions. Finally, the key findings with regards to further research required for the processing of advanced high-strength steels of third generation have been discussed.

Mullite Whisker Reinforced Zirconia Toughened Alumina for High Temperature Applications

2014 ◽  
Author(s):  
Taylor Robertson ◽  
Xiao Huang ◽  
Richard Kearsey
Keyword(s):  
High Temperature ◽  
Cost Effective ◽  
Mechanical Tests ◽  
Processing Route ◽  
Molten Salt Method ◽  
The Matrix ◽  
Mullite Whiskers ◽  
Monolithic Ceramics ◽  
Zirconia Toughened Alumina ◽  
Temperature Applications

Particulate enhanced oxide ceramics are an attractive class of materials for high temperature applications because they possess many of the high temperature capabilities of monolithic ceramics but also have enhanced mechanical properties due to their multi-phase structure. High temperature structural ceramics have the potential to operate above at higher temperatures than current super alloys; however, processing costs and lack of reliability has prevented their commercialization. In this work a particulate reinforced ceramic composed entirely of oxides is proposed as a more oxidation resistant and cost effective structural ceramic which will have potentially improved resistance to environmental degradation. Zirconia Toughened Alumina (ZTA), as the matrix, has enhanced toughness, strength, and creep resistance over single phase alumina or zirconia. ZTA can further be strengthened by the incorporation of SiC type whiskers; however, these whiskers are prone to deterioration at temperatures above 1000°C through oxidation. In this work Mullite, in whisker form, is proposed as the reinforcement to ZTA due to its stability in oxidizing atmospheres at high temperatures. Mullite whiskers are grown through the molten salt method and incorporated into the ZTA matrix using a colloidal processing route in this study. The composition of the ZTA matrix is 15wt% Yttria stabilized Zirconia (YSZ), 85 wt% α-Alumina. The Mullite whiskers make up 20 vol% of the composite, yielding a final composition of 71.6 wt% Alumina, 12.7 wt% YSZ, and 15.6 wt% Mullite. The green compacts are fired in a two stage sintering process incorporating atmospheric pressure sintering to 92% density (seal the pore channels) and then hot isostatic pressure pressing (HIP) to increase the density. Samples have been tested for room temperature flexural strength using a three point bend test and fracture toughness through Gong’s Vickers indentation method. The results of microstructure study and mechanical tests are reported in this paper.

Electroplating and Electroless Plating Process Development for DuPont™ GreenTape™ 9K7 LTCC

2013 ◽  
Vol 2013 (CICMT) ◽  
pp. 000283-000287
Author(s):  
Allan Beikmohamadi ◽  
Steve Stewart ◽  
Jim Parisi ◽  
Mark McCombs ◽  
Michael Smith ◽  
...  
Keyword(s):  
Thick Film ◽  
Surface Finish ◽  
Electroless Plating ◽  
Process Development ◽  
Cost Effective ◽  
Electroless Nickel ◽  
Free Atmosphere ◽  
Gold Plating ◽  
Cost Effective Approach ◽  
Easy Integration

Low Temperature Co-fired Ceramic (LTCC) technology provides an attractive packaging platform for microwave and millimeter wave circuits and systems due to its unique properties. Generally, thick film gold or silver conductors are used as metallizations on LTCC substrates along with occasional use of copper thick films. This paper reports methods and results of extensive process development experiments DuPont Microcircuit Materials has undertaken to establish a commercially viable plating process for the market leading DuPont™ GreenTape™ 9K7 LTCC system. Both Electroplating and Electroless plating processes are investigated in this work. These techniques provide certain advantages when used in isolation or in combination with standard thick film metallizations, helping to extend their applicability. Electroplating of copper on LTCC provides a means of using copper as the external conductor without having to use complicated firing processes in oxygen-free atmosphere as required for copper thick film. This approach leads to a much more cost effective approach if copper is required as the external metal. Electroless Nickel/Gold plating (ENIG) of both silver and copper (electroplated and/or thick film) provides an industry standard, highly reliable, robust surface finish. Such surface finish enables easy integration of both soldering and wire bonding processes.

Synthesis of Nanostructured Magnetic Mixed-Oxide Ferrite Powders by Using A Novel Chemical Method

2002 ◽  
Vol 720 ◽  
Author(s):  
N N Ghosh
Keyword(s):  
Particle Size ◽  
Mixed Oxide ◽  
Chemical Method ◽  
Average Particle Size ◽  
Cost Effective ◽  
Water Soluble ◽  
Average Particle ◽  
Chemical Route ◽  
Water Soluble Polymer ◽  
Different Temperatures

AbstractIn the present investigation, an attempt has been made to establish a new chemical route for synthesis of the nanostructured mixed oxide ferrite powders. By using this chemical method a variety of ferrite powders having spinel structure and doped with Co, Ni, Mn, Zn etc has been prepared. In this method nitrate salts of the different metals were used as starting materials. The aqueous solutions of the metal nitrates were mixed according to the molar ration of the compositions. Then the mixtures were mixed with an aqueous solution of water soluble polymer (polyvinyl alcohol). This mixture after drying yield fluffy brown powders. These powders were then calcined at different temperatures ranging from 400 °C to 700 °C. Nanostructured powders were obtained from the thermal decomposition of the brown powders. The powders, prepared by calcinations at different temperatures, were characterized by using X-Ray diffraction analysis, IR spectroscopy, TGA/DTA, and TEM. It was observed that the average particle size of the powders are in nanometer scale with a narrow size distribution. The average particle size of the powders was increased with the increase of calcinations temperature.This chemical method has proved to provide a convenient process for the preparation of nanostructured ceramic powders at comparatively low temperatures and offers the potential of being a simple and cost-effective route.

Pervaporative desalination of seawater using a polyvinylidene fluoride based membrane

2017 ◽  
Vol 18 (5) ◽  
pp. 1674-1681 ◽  
Author(s):  
F. U. Nigiz ◽  
N. D. Hilmioglu
Keyword(s):  
Fresh Water ◽  
Polyvinylidene Fluoride ◽  
High Performance ◽  
Potable Water ◽  
Effective Properties ◽  
Cost Effective ◽  
Porous Membranes ◽  
Scientific Investigations ◽  
Different Temperatures ◽  
Energy Strategies

Abstract Producing a fresh water supply by converting non-potable water is an attractive solution when water is scarce. According to the energy strategies of different countries, various seawater purification techniques such as distillation and reverse osmosis (RO) are used to produce fresh water. Due to the selective separation capability and cost-effective properties, membrane based methods such as RO, electrodialysis, and ultra/micro/nano/filtration are prevalent, especially in Europe. Recently, innovative desalination technologies have been investigated by researchers. Among them, pervaporative separation, in which non-porous membranes are used, appears to be an emerging and promising method. The key part of the system is the membrane. Hence, scientific investigations are focused on the production of high-performance membranes. In this study, non-porous polyvinylidene fluoride (PVDF) and polyvinyl pyrrolidone (PVP) blend membranes were prepared in different PVDF/PVP ratios and Marmara seawater was desalinated using the pervaporation method at different temperatures. Desalination performance was evaluated as a function of flux and salt retention. The highest salt retention of 99.90% and flux of 1.60 kg/m2.h were obtained at 60 °C when the PVDF/PVP ratio was 1.5.

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