scholarly journals The influence of electrocorundum granulation on the properties of sintered Cu/electrocorundum composites

2015 ◽  
Vol 47 (3) ◽  
pp. 249-258 ◽  
Author(s):  
A. Strojny-Nędza ◽  
K. Pietrzak ◽  
W. Węglewski
Keyword(s):  
Thermal Conductivity ◽  
Aerospace Industry ◽  
Particle Sizes ◽  
Aircraft Engines ◽  
Sintering Process ◽  
Good Resistance ◽  
Frictional Wear ◽  
High Specific Heat ◽  
Alumina Composites ◽  
Ceramic Reinforcement

Copper/alumina composites are extensively used in automotive and aerospace industry for products that are subjected to severe thermal and mechanical loadings, such as rocket thrusters and components of aircraft engines. These materials are well-known for their good frictional wear resistance, good resistance to thermal fatigue, high thermal conductivity and high specific heat. In this paper, the sintering process of copper/electrocorundum composites reinforced by electrocorundum particles with diameters of 3 or 180 ?m and 1, 3, 5 vol.% content is presented. The effects of different particle sizes of the ceramic reinforcement on the microstructure, physical, mechanical, tribological and thermal properties of the fabricated composites are discussed.

scholarly journals A Comparative Study of Mechanical Properties, Thermal Conductivity, Residual Stresses, and Wear Resistance of Aluminum-Alumina Composites Obtained by Squeeze Casting and Powder Metallurgy

2021 ◽  
Author(s):  
Justyna Maj ◽  
Witold Węglewski ◽  
Kamil Bochenek ◽  
Łukasz Rogal ◽  
Stefania Woźniacka ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Powder Metallurgy ◽  
Residual Stresses ◽  
Squeeze Casting ◽  
Processing Route ◽  
Thermal Residual Stresses ◽  
Frictional Wear ◽  
Potential Applications ◽  
Alumina Composites ◽  
The Impact

AbstractSqueeze casting and powder metallurgy techniques were employed to fabricate AlSi12/Al2O3 composites, which are lightweight structural materials with potential applications in the automotive industry. The impact of the processing route on the material properties was studied. Comparative analyses were conducted for the Vickers hardness, flexural strength, fracture toughness, thermal conductivity, thermal residual stresses, and frictional wear. Our results show that the squeeze cast composite exhibits superior properties to those obtained using powder metallurgy.

BRUSH ALLOY 3

Alloy Digest ◽  
1983 ◽  
Vol 32 (3) ◽  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
Copper Alloy ◽  
Elevated Temperatures ◽  
Physical And Mechanical Properties ◽  
Heat Treating ◽  
Good Resistance ◽  
Good Corrosion Resistance

Abstract BRUSH Alloy 3 offers the highest electrical and thermal conductivity of any beryllium-copper alloy. It possesses an excellent combination of moderate strength, good corrosion resistance and good resistance to moderately elevated temperatures. Because of its unique physical and mechanical properties, Brush Alloy 3 finds widespread use in welding applications (RWMA Class 3), current-carrying springs, switch and instrument parts and similar components. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on corrosion resistance as well as casting, forming, heat treating, machining, joining, and surface treatment. Filing Code: Cu-454. Producer or source: Brush Wellman Inc..

scholarly journals Improvement of mechanical properties of HfB2-based composites by incorporating in situ SiC reinforcement through pressureless sintering

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Ghadami ◽  
E. Taheri-Nassaj ◽  
H. R. Baharvandi ◽  
F. Ghadami
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Relative Density ◽  
Pressureless Sintering ◽  
Sintering Process ◽  
Vacuum Atmosphere ◽  
Sic Reinforcement ◽  
Microstructural Studies ◽  
Composite Samples

AbstractHfB2, Si, and activated carbon powders were selected to fabricate 0–30 vol% SiC reinforced HfB2-based composite. Pressureless sintering process was performed at 2050 °C for 4 h under a vacuum atmosphere. Microstructural studies revealed that in situ SiC reinforcement was formed and distributed in the composite according to the following reaction: Si + C = SiC. A maximum relative density of 98% was measured for the 20 vol% SiC containing HfB2 composite. Mechanical investigations showed that the hardness and the fracture toughness of these composites were increased and reached up to 21.2 GPa for HfB2-30 vol% SiC and 4.9 MPa.m1/2 for HfB2-20 vol% SiC, respectively. Results showed that alpha-SiC reinforcements were created jagged, irregular, and elongated in shape which were in situ formed between HfB2 grains and filled the porosities. Formation of alpha-SiC contributed to improving the relative density and mechanical properties of the composite samples. By increasing SiC content, an enhanced trend of thermal conductivity was observed as well as a reduced trend for electrical conductivity.

scholarly journals Master sintering curve: A practical approach to its construction

2010 ◽  
Vol 42 (1) ◽  
pp. 25-32 ◽  
Author(s):  
V. Pouchly ◽  
K. Maca
Keyword(s):  
Activation Energy ◽  
Practical Method ◽  
Practical Approach ◽  
Particle Sizes ◽  
Sintering Process ◽  
Cubic Zirconia

The concept of a Master Sintering Curve (MSC) is a strong tool for optimizing the sintering process. However, constructing the MSC from sintering data involves complicated and time-consuming calculations. A practical method for the construction of a MSC is presented in the paper. With the help of a few dilatometric sintering experiments the newly developed software calculates the MSC and finds the optimal activation energy of a given material. The software, which also enables sintering prediction, was verified by sintering tetragonal and cubic zirconia, and alumina of two different particle sizes.

Brownian-Motion-Based Convective-Conductive Model for the Effective Thermal Conductivity of Nanofluids

2005 ◽  
Vol 128 (6) ◽  
pp. 588-595 ◽  
Author(s):  
Ravi Prasher ◽  
Prajesh Bhattacharya ◽  
Patrick E. Phelan
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Particle Sizes ◽  
Brownian Movement ◽  
Liquid Temperature ◽  
Interfacial Resistance ◽  
Conduction Model ◽  
Order Of Magnitude ◽  
Base Liquid ◽  
Good Agreement

Here we show through an order-of-magnitude analysis that the enhancement in the effective thermal conductivity of nanofluids is due mainly to the localized convection caused by the Brownian movement of the nanoparticles. We also introduce a convective-conductive model which accurately captures the effects of particle size, choice of base liquid, thermal interfacial resistance between the particles and liquid, temperature, etc. This model is a combination of the Maxwell-Garnett (MG) conduction model and the convection caused by the Brownian movement of the nanoparticles, and reduces to the MG model for large particle sizes. The model is in good agreement with data on water, ethylene glycol, and oil-based nanofluids, and shows that the lighter the nanoparticles, the greater the convection effect in the liquid, regardless of the thermal conductivity of the nanoparticles.

Study of Sawdust and Expanded Polystyrene as Cavity Filler Material on the Effect of Thermal Conductivity in Perforated Clay Brick

2017 ◽  
Vol 890 ◽  
pp. 411-414
Author(s):  
Mun Kou Lai ◽  
Abdullah Salem Basalem Maged
Keyword(s):  
Thermal Conductivity ◽  
Specific Heat ◽  
Temperature Change ◽  
Electricity Consumption ◽  
Expanded Polystyrene ◽  
Filler Material ◽  
Waste Products ◽  
High Specific Heat ◽  
Building Wall ◽  
Good Potential

The main objective of this paper is to reduce the amount of external heat penetrating the building wall, hence reducing the cooling load requirements and eventually the electricity consumption. Expanded polystyrene and wood sawdust were chosen as filler material to reduce the thermal conductivity in perforated bricks because both are commonly found waste products with good potential due to their lightweight, low thermal conductivity and high specific heat. It was found that bricks with polystyrene recorded the lowest temperature change. Although sawdust has a much higher thermal conductivity, the temperature change is almost similar to that of polystyrene. This could be attributed by the higher density of wood, which means more mass are occupying the same volume of space. Hence, the paper found that thermal conductivity, specific heat capacity and density of the filler material can influence the effective thermal conductivity of the perforated brick.

Binary Particle Mixtures as a Heat Transfer Media in Shell-and-Plate Moving Packed Bed Heat Exchangers

2021 ◽  
Author(s):  
Chase Ellsworth Christen
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Particle Size ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Packed Bed ◽  
Particle Sizes ◽  
Overall Heat Transfer Coefficient ◽  
Solid Media

Solid particles are being considered in several high temperature thermal energy storage systems and as heat transfer media in concentrated solar power (CSP) plants. The downside of such an approach is the low overall heat transfer coefficients in shell-and-plate moving packed bed heat exchangers caused by the inherently low packed bed thermal conductivity values of the low-cost solid media. Choosing the right particle size distribution of currently available solid media can make a substantial difference in packed bed thermal conductivity, and thus, a substantial difference in the overall heat transfer coefficient of shell-and-plate moving packed bed heat exchangers. Current research exclusively focuses on continuous unimodal distributions of alumina particles. The drawback of this approach is that larger particle sizes require wider particle channels to meet flowability requirements. As a result, only small particle sizes with low packed bed thermal conductivities have been considered for the use in the falling-particle Gen3 CSP concepts. Here, binary particle mixtures, which are defined in this thesis as a mixture of two continuous unimodal particle distributions leading to a continuous bimodal particle distribution, are considered to increase packed bed thermal conductivity, decrease packed bed porosity, and improve moving packed bed heat exchanger performance. This is the first study related to CSP solid particle heat transfer that has considered the packed bed thermal conductivity and moving packed bed heat exchanger performance of bimodal particle size distributions at room and elevated temperatures. Considering binary particle mixtures that meet particle sifting segregation criteria, the overall heat transfer coefficient of shell-and-plate moving packed bed heat exchangers can be increased by 23% when compared to a monodisperse particle system. This work demonstrates that binary particle mixtures should be seriously considered to improve shell-and-plate moving packed bed heat exchangers.

The Effect of Vuggy Porosity on Straining in Porous Media

SPE Journal ◽  
2019 ◽  
Vol 24 (03) ◽  
pp. 1164-1178 ◽  
Author(s):  
Hasan J. Khan ◽  
Maša Prodanovic ◽  
David A. DiCarlo
Keyword(s):  
Glass Beads ◽  
Surface Forces ◽  
Particle Sizes ◽  
Sintering Process ◽  
The Core ◽  
Maximum Change ◽  
Flow Experiment ◽  
The Matrix ◽  
Flow Configurations ◽  
Shape Changes

Summary A formation-damage experimental study is conducted on synthetic homogeneous and vuggy cores. Glass beads of 1.0 mm are sintered to form a uniform core with a porosity of 42%, and finer-sized glass beads (25 and 100 µm) are used as the infiltrates. Glass beads are used as the matrix and infiltrate to reduce surface forces, and the flow is gravity dominated. Dissolvable inclusions are added during the sintering process to create vugs in the core. The pore-size to vug-size ratio is 1:100. The injected-particle sizes are chosen such that straining is the dominant trapping mechanism during the flow experiment. Infiltrate particles are injected at different flow configurations, and the resultant porosity, permeability, and effluent volume are measured. The results can be summarized as follows: Vugs get up to 32% smaller caused by the flow for the infiltrate, while the maximum change in the porosity is observed at the bottom end of the core, vug shape changes to a smoother and rounded surface, and particles go deeper (8 mm more) into the formation when vugs are present, causing damage deeper inside the formation.

scholarly journals Mechanical Properties and Microstructure of W-6Ni-4Co Alloy by a Two-Step Sintering Process

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 680 ◽  
Author(s):  
Hongfeng Dong ◽  
Peiyou Li ◽  
Taotao Ai ◽  
Wenhu Li
Keyword(s):  
Mechanical Properties ◽  
Mechanical Alloying ◽  
Solid Phase ◽  
Particle Sizes ◽  
Sintering Process ◽  
Dwelling Time ◽  
Milled Powders

The mechanical properties and microstructure of W-6Ni-4Co alloy through solid phase sintering and two-step sintering process were investigated. The results demonstrated that the particle sizes of W-6Ni-4Co alloy milled powders increased firstly and decreased later during a mechanical alloying process. The shape of alloy milled powders affected that of grains in alloy by solid phase sintering. The shape of W-rich particles in the alloys changed from stripes to network, to polygonal and to subsphaeroidal finally during two-step sintering process. The mechanical properties could be attributed to the densification and microstructure of alloys, and increased during two-step sintering with short dwelling time.

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