Synthesis of Porous SiC Preform and Squeeze Infiltration Processing of Aluminium-SiC Metal Ceramic Composites

2012 ◽  
Vol 710 ◽  
pp. 371-376 ◽  
Author(s):  
K.M. Sree Manu ◽  
V.G. Resmi ◽  
M. Brahmakumar ◽  
N. Anand ◽  
T.P.D. Rajan ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Porous Ceramic ◽  
Ceramic Composites ◽  
Al Alloy ◽  
Pore Former ◽  
Squeeze Pressure ◽  
Sic Particles ◽  
Squeeze Infiltration ◽  
Ceramic Preform ◽  
Metal Ceramic

Metal-Ceramic Composites with high volume fraction of reinforcement find wide applications in the area of tribology and high temperature resistant components like piston, brake pads, heat shields etc. Most of these components can be made by infiltration processing of porous ceramic preforms. The present investigation is to synthesize porous ceramic preform based on SiC particles using inorganic salt as a pore forming agent and Squeeze infiltration is applied to fabricate the Al-SiC metal-ceramic composites. The direct squeeze infiltration of 6061 aluminum alloy on SiC preform is successfully carried out with the controlled process parameters of initial preform temperature, liquid metal superheat, squeeze pressure and its rate of application, and die temperature. The preform and composites are characterized using XRD, optical microscopy, electron microscopy, and hardness and compression strength. Porous ceramic preform with more than 50% porosity has been fabricated by sodium chloride as pore former. The infiltrated composite have shown uniform and complete infiltration of Aluminium alloy in between SiC particles and posses very high hardness of 147 BHN in as cast condition compared to 57 BHN for the 6061 Al alloy.

Development of Al 319-Micro Silica Metallic Composite by Squeeze Infiltration Technique

2015 ◽  
Vol 830-831 ◽  
pp. 489-492 ◽  
Author(s):  
K.M. Sree Manu ◽  
P.S. Rahul ◽  
L. Ajay Raag ◽  
T.P.D. Rajan ◽  
M Brahmakumar ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Porous Ceramic ◽  
Ceramic Composites ◽  
Pore Former ◽  
Squeeze Pressure ◽  
Squeeze Infiltration ◽  
Ceramic Preform ◽  
Infiltration Technique ◽  
Temperature Liquid ◽  
Micro Silica

The objective of present investigation is to synthesize porous micro silica based ceramic preform with varying composition of particles using burn out technique and processing of Al-Micro silica metal-ceramic composites by squeeze infiltration method. Direct squeeze infiltration of 319 aluminum alloy on micro silica preform is successfully carried out with the controlled process parameters of initial preform temperature, liquid metal superheat, squeeze pressure and its rate of application, and die temperature. The preform and composites are characterized using optical microscopy, electron microscopy, hardness and compression strength testing. Porous ceramic preform with more than 70% porosity has been fabricated by PEG as pore former. The infiltrated composite have shown uniform and complete infiltration of aluminum alloy in between micro silica particles.

Material Parameter Identification of Interpenetrating Metal-Ceramic Composites

2009 ◽  
Vol 417-418 ◽  
pp. 53-56 ◽  
Author(s):  
Romana Piat ◽  
Siddharta Roy ◽  
Alexander Wanner
Keyword(s):  
Porous Ceramic ◽  
Micromechanical Model ◽  
Polarized Light ◽  
Ceramic Composites ◽  
Material Parameter Identification ◽  
Casting Technique ◽  
New Class ◽  
Ceramic Preform ◽  
Metal Ceramic ◽  
Manufacturing Parameters

A new class of metal/ceramic composites has recently been developed. A porous ceramic preform, the pore structure of which is created via a freeze-casting technique, is melt-infiltrated with metallic alloy via sqzeeze-casting. The microstructure of the composite has lamellar-like domains with geometrical characteristics which are dependent on the manufacturing parameters. The aim of our study is to find a good micromechanical model in order to deduce the mechanical properties of the single domains and of the whole material as a function of the microstructural geometry and the material parameters of the ceramics (alumina) and the alloy (Al-Si eutectic). Firstly, the statistical analysis of polarized light microscopic micrographs of the cross section of the specimen was performed. Domains with the same orientation of lamellae, so-called single domains were detected, selected and measured. The material modeling was performed by a two-step homogenisation procedure using a combination of different micromechanical models. Predicted material properties were compared with ultrasonic measurements for a single domain and for the whole microstructure.

scholarly journals Centrifugal Infiltration of Porous Ceramic Preforms by the Liquid Al Alloy – Theoretical Background and Experimental Verification

2016 ◽  
Vol 61 (1) ◽  
pp. 411-418 ◽  
Author(s):  
A.J. Dolata
Keyword(s):  
Heat Exchange ◽  
Liquid Metal ◽  
Experimental Verification ◽  
Porous Ceramic ◽  
Specific Area ◽  
Ceramic Materials ◽  
Theoretical Background ◽  
Al Alloy ◽  
Ceramic Preform ◽  
Porous Ceramic Materials

The goal of this work is the description of phenomena occurring during centrifugal infiltration of porous ceramic materials by liquid Al alloy. In this method, the pressure required to infiltration of liquid metal into pores of ceramic is generated by centrifugal force. From the beginning it was assumed that the porous ceramic material will create reinforcement layer in specific area of the casting. The forces that influence on the liquid metal during mould centrifugation and heat exchange between ceramic preform and metal alloy within the area of the front of infiltration were considered in the analysis. The paper presents also selected experiment results.

Strengthening Behavior and Tension–Compression Strength–Asymmetry in Nanocrystalline Metal–Ceramic Composites

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
A. M. Dongare ◽  
B. LaMattina ◽  
A. M. Rajendran
Keyword(s):  
Molecular Dynamics ◽  
Volume Fraction ◽  
Md Simulations ◽  
Ceramic Composites ◽  
Embedded Atom Method ◽  
Nanocrystalline Metal ◽  
Rich Region ◽  
Embedded Atom ◽  
Metal Ceramic ◽  
Strength Asymmetry

Metal–ceramic composites are an emerging class of materials for use in the next-generation high technology applications due to their ability to sustain plastic deformation and resist failure in extreme mechanical environments. Large scale molecular dynamics simulations are used to investigate the performance of nanocrystalline metal–matrix composites (MMCs) formed by the reinforcement of the nanocrystalline Al matrix with a random distribution of nanoscale ceramic particles. The interatomic interactions are defined by the newly developed angular-dependent embedded atom method (A-EAM) by combining the embedded atom method (EAM) potential for Al with the Stillinger–Weber (SW) potential for Si in one functional form. The molecular dynamics (MD) simulations are aimed to investigate the strengthening behavior and the tension–compression strength asymmetry of these composites as a function of volume fraction of the reinforcing Si phase. MD simulations suggest that the strength of the nanocomposite increases linearly with an increase in the volume fraction of Si in the Al-rich region, whereas the increase is very sharp in the Si-rich region. The higher strength of the nanocomposite is attributed to the reduced sliding/rotation between the Al/Si and the Si/Si grains as compared to the pure nanocrystalline metal.

Friction Stir Welding of SiCp/Al Composite and 2024 Al Alloy

2010 ◽  
Vol 638-642 ◽  
pp. 1500-1505 ◽  
Author(s):  
B.L. Xiao ◽  
Dong Wang ◽  
J. Bi ◽  
Z. Zhang ◽  
Z.Y. Ma
Keyword(s):  
Friction Stir Welding ◽  
Heat Affected Zone ◽  
Volume Fraction ◽  
Ring Structure ◽  
Al Alloy ◽  
Friction Stir ◽  
Sic Particles ◽  
Al Composite ◽  
Clad Layer ◽  
Tool Pin

6 mm thick SiCp/2009Al composite and 2024Al-T351 alloy plates were successfully joined by friction stir welding (FSW) with and without the tool pin offsetting to the 2024Al side (denoted as NOS and OS samples, respectively), producing defect-free joints. The SiC particles from the composite were distributed along a ring structure in the nugget and the volume fraction of the SiC particles decreased as the tool pin offset to the 2024Al side. The Al-clad layer on the 2024Al plate was aggregated on the retreating side of the nugget after FSW. For the OS sample, the Al formed a layer along the nugget boundary. The strength of the NOS sample reached up to 85% of the 2024Al alloy with the joint failing in the heat affected zone on the 2024Al side. The strength of the OS samples was 47% of the 2024Al alloy due to the aggregated Al layer on the retreating side of the nugget which decreased the strength of the joint.

Residual stresses in novel metal/ceramic composites exhibiting a lamellar microstructure

2009 ◽  
Vol 24 (S1) ◽  
pp. S59-S64 ◽  
Author(s):  
Siddhartha Roy ◽  
Jens Gibmeier ◽  
Alexander Wanner
Keyword(s):  
Residual Stresses ◽  
Porous Ceramic ◽  
Lamellar Microstructure ◽  
Cost Effective ◽  
High Energy ◽  
Ceramic Composites ◽  
Aluminum Silicon Alloy ◽  
Spatially Resolved ◽  
Production Route ◽  
Metal Ceramic

The aim of this study is to analyze the mechanics of a new class of metal/ceramic composites on a mesoscopic length scale. These composites are produced by melt infiltration of porous ceramic preforms produced by freeze casting and subsequent sintering. This production route has a high application potential since it offers a cost-effective way to obtain composites with ceramic content in the 30 to 70 vol.%range. The as-produced material exhibits a hierarchical domain structure with each domain composed of alternating layers of metallic and ceramic lamellae. Residual stresses present in all phases of the composite produced by infiltrating alumina preforms with a eutectic aluminum-silicon alloy have been measured. Integral as well as spatially resolved measurements were carried out on single-domain samples at the high-energy, energy-dispersive diffraction (EDDI) beamline at the synchrotron radiation source BESSY (Berlin, Germany). Results show that strongly fluctuating residual stresses are introduced by the production process, which can be rationalized by taking into account the thermal expansion mismatch of alloy and preform.

Numerical Prediction of Effective Transformation Properties of Hybrid SMA-Ceramic Composites

2010 ◽  
Author(s):  
Brian Lester ◽  
Yves Chemisky ◽  
Dimitris Lagoudas
Keyword(s):  
Volume Fraction ◽  
Extreme Environments ◽  
Ceramic Composites ◽  
Metal Phase ◽  
New Materials ◽  
Ceramic Phase ◽  
Micromechanical Approach ◽  
Metal Ceramic ◽  
As Stress ◽  
Effective Phase

Metal-ceramic composites are being increasingly explored in an effort to find new materials for use in extreme environments. Via functional grading of of the volume fraction of the constituant phases and other techniques, the material can be optimized to incorporate the mechanical properties of the metal phase with the thermal properties of the ceramic phase. To get further benefit of the metal phase, a new area being investigated is the incorporation of Shape Memory Alloys (SMAs). In order to predict the phase transformation features of an SMA embedded in a stiff ceramic matrix, a micromechanical approach is developed to find the effective phase diagram of the ceramic-SMA composite. From this analysis, other composite characteristics such as stress in each phase and the evolution of tranformation strain in the SMA can be determined in order to improve the design of such new composite materials.

Squeeze Infiltration Processing of Functionally Graded Aluminum–SiC Metal Ceramic Composites

2012 ◽  
Vol 65 (6) ◽  
pp. 747-751 ◽  
Author(s):  
K. M. Sree Manu ◽  
V. G. Resmi ◽  
M. Brahmakumar ◽  
P. Narayanasamy ◽  
T. P. D. Rajan ◽  
...  
Keyword(s):  
Ceramic Composites ◽  
Functionally Graded ◽  
Squeeze Infiltration ◽  
Metal Ceramic

scholarly journals A Thermally Conductive Pt/AAO Catalyst for Hydrogen Passive Autocatalytic Recombination

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 491
Author(s):  
Alina E. Kozhukhova ◽  
Stephanus P. du Preez ◽  
Aleksander A. Malakhov ◽  
Dmitri G. Bessarabov
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Combustion Temperature ◽  
Volume Fraction ◽  
Morphological Characteristics ◽  
Al Alloy ◽  
Impregnation Method ◽  
Case Scenario ◽  
Worst Case ◽  
Thermal Distribution

In this study, a Pt/anodized aluminum oxide (AAO) catalyst was prepared by the anodization of an Al alloy (Al6082, 97.5% Al), followed by the incorporation of Pt via an incipient wet impregnation method. Then, the Pt/AAO catalyst was evaluated for autocatalytic hydrogen recombination. The Pt/AAO catalyst’s morphological characteristics were determined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The average Pt particle size was determined to be 3.0 ± 0.6 nm. This Pt/AAO catalyst was tested for the combustion of lean hydrogen (0.5–4 vol% H2 in the air) in a recombiner section testing station. The thermal distribution throughout the catalytic surface was investigated at 3 vol% hydrogen (H2) using an infrared camera. The Al/AAO system had a high thermal conductivity, which prevents the formation of hotspots (areas where localized surface temperature is higher than an average temperature across the entire catalyst surface). In turn, the Pt stability was enhanced during catalytic hydrogen combustion (CHC). A temperature gradient over 70 mm of the Pt/AAO catalyst was 23 °C and 42 °C for catalysts with uniform and nonuniform (worst-case scenario) Pt distributions. The commercial computational fluid dynamics (CFD) code STAR-CCM+ was used to compare the experimentally observed and numerically simulated thermal distribution of the Pt/AAO catalyst. The effect of the initial H2 volume fraction on the combustion temperature and conversion of H2 was investigated. The activation energy for CHC on the Pt/AAO catalyst was 19.2 kJ/mol. Prolonged CHC was performed to assess the durability (reactive metal stability and catalytic activity) of the Pt/AAO catalyst. A stable combustion temperature of 162.8 ± 8.0 °C was maintained over 530 h of CHC. To confirm that Pt aggregation was avoided, the Pt particle size and distribution were determined by TEM before and after prolonged CHC.

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