Interface characterization of metal matrix composites by transmission electron microscopy

1987 ◽  
Vol 45 ◽  
pp. 304-305
Author(s):  
I. W. Hall ◽  
A. P. Diwanji
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Matrix Alloy ◽  
Matrix Composites ◽  
Structure Property ◽  
Manufacturing Method ◽  
Transmission Electron ◽  
Structural Applications

Carbon fiber reinforced metal matrix composites (MMC's) are an attractive class of materials for automotive and aerospace structural applications because of their high strength and stiffness to weight ratios and their low coefficients of thermal expansion. Successful development of these new materials demands a thorough understanding of the structure/property/processing relationships and, in particular, a detailed understanding of the fiber/matrix interface since this region strongly influences the final mechanical properties of the system. This interface is affected by many factors including the manufacturing method, heat treatment, matrix alloy composition and wettability of the fibers but, since it is a region which is typically much less than lμm wide, it is inaccessible to direct detailed observation by any means other than transmission electron microscopy.

Influences of Strontium Addition and Whisker Content on Solidification Behavior of SiCw/Al-18Si Metal Matrix Composites

2006 ◽  
Vol 15-17 ◽  
pp. 251-254
Author(s):  
Hong Mei Wei ◽  
Lin Geng ◽  
Xue Xi Zhang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Matrix Composites ◽  
Solidification Behavior ◽  
Primary Si ◽  
Transmission Electron ◽  
Scanning Electron

Solidification behavior of SiCw/Al-18Si metal matrix composites (MMCs) was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and differential scanning calorimeter (DSC) in order to reveal the effects of strontium addition and whisker content. The results show that the Si phase does not nucleate on SiC whisker surface. With the increasing of SiC whisker content, solidification onset and peak temperatures of primary Si decrease. Sr addition lowers solidification onset and peak temperatures of primary Si, and reduces its size. Whisker content has larger effects on solidification onset and peak temperatures of primary Si without Sr addition than that of primary Si with Sr addition.But solidification onset and peak temperatures of eutectic are barely affected by whisker content and Sr addition.

Thermal and mechanical properties of mechanically alloyed 304LSS-CNT metal matrix composites

2016 ◽  
Vol 51 (7) ◽  
pp. 1019-1028 ◽  
Author(s):  
Caleb Massey ◽  
Manuel Umanzor ◽  
Gokul Vasudevamurthy
Keyword(s):  
Electron Microscopy ◽  
Thermal Diffusivity ◽  
Mechanical Alloying ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Matrix Composites ◽  
Mechanically Alloyed ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Increased Strength

A methodology for the creation of 304LSS-CNT metal matrix composites using the mechanical alloying approach is presented. Planetary ball milled powders were both melted and hot pressed and achieved up to 96% theoretical density. High resolution scanning electron microscopy, Scanning Transmission Electron Microscopy, X-ray diffraction, energy dispersive spectroscopy, thermal diffusivity measurements, and Vickers microhardness measurements are used to characterize as processed and heat treated composites. Melted and solidified samples show highly anisotropic austenite/martensite microstructures with the presence of large dendritic carbon agglomerations, while hot-pressed samples show equiaxed austenite/martensite grains with a large number density of carbide precipitates. Grain size and thermal diffusivity decrease while microhardness increases up to 36% with up to 2% carbon nanotube addition for hot-pressed samples. Thus, mechanical alloying has been shown to be a potential option for the production of homogeneous 304LSS-CNT metal matrix composites for applications requiring increased strength.

Effects of waste eggshells and SiC addition in the synthesis of aluminum hybrid green metal matrix composite

2017 ◽  
Vol 6 (1) ◽  
Author(s):  
Shashi Prakash Dwivedi ◽  
Satpal Sharma ◽  
Raghvendra Kumar Mishra
Keyword(s):  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Weight Ratio ◽  
Matrix Alloy ◽  
The Other ◽  
Matrix Composites ◽  
Transmission Electron ◽  
Aa2014 Alloy ◽  
The Matrix ◽  
Electron Microscope Image

AbstractThe mechanical behavior, physical behavior, microstructural characteristics, and corrosion behavior of AA2014/silicon carbide (SiC)/carbonized eggshell hybrid green metal matrix composites (MMCs) were investigated. Twenty-five samples of hybrid composite with different combinations of SiC and carbonized eggshell particles in AA2014 matrix alloy were prepared. Microstructure presents that the reinforcement particles (SiC and eggshells) are uniformly distributed in the matrix AA2014 alloy. Transmission electron microscope image shows proper wettability between SiC, carbonized eggshell, and AA2014 aluminum alloy. The tensile strength and the fatigue strength for the composites containing 2.5 wt.% SiC up to 7.5 wt.% carbonized eggshell were observed to be higher than that of the other selected composites. The hardness values for the composites containing 12.5 wt.% SiC and 2.5 wt.% carbonized eggshell were in all cases higher than that of the other composites. The results show that toughness decreases with the increase in the weight ratio of SiC and carbonized eggshell in the composites. The results reveal that the sample of AA2014/2.5% SiC/12.5% carbonized eggshell shows minimum corrosion rate among all the selected samples. Density, porosity, and overall cost of hybrid metal matrix composites were also calculated to see the effects of carbonized eggshell and SiC addition in AA2014 matrix alloy.

Interfacial Reactions in Metal-Matrix Composites

1995 ◽  
Vol 398 ◽  
Author(s):  
J. R. Heffelfinger ◽  
R. R. Kieschke ◽  
C. B. Carter
Keyword(s):  
Electron Microscopy ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Ti Alloy ◽  
Matrix Composites ◽  
Reaction Products ◽  
Alloy Matrix ◽  
Β Phase ◽  
Transmission Electron ◽  
The Matrix

ABSTRACTThe interfacial reaction between Al2O3 (alumina) and a β-Ti alloy has been characterized by transmission electron microscopy, scanning electron microscopy, and X-ray energy-dispersive spectroscopy. Diffusion bonding single-crystal alumina and a β-Ti alloy was found to produce three interfacial regions: a region of intermetallics (Tl3Al and TiAl) located near the alumina interface, an α-Ti region, and a β-Ti region (rich in Mo, the β-phase stabilizer). Of the intermetallics to form, Ti3Al was found to form first and have an aligned, planar interface with the alumina. TiAl formed second and was found to separate grains of Ti3Al and the alumina. Reaction products observed in the diffusion-bonded alumina/β-Ti couples are compared with those observed in metal-matrix composites (MMCs), where a β-Ti alloy matrix is reinforced with alumina fibers. Different coatings used in MMCs are investigated for their ability to prevent the reaction between the matrix and fibers.

The role of microscopy in the development of metal matrix composites

1992 ◽  
Vol 50 (1) ◽  
pp. 162-163
Author(s):  
Gilles L'Espérance ◽  
David J. Lloyd
Keyword(s):  
Electron Microscopy ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Grain Structure ◽  
Analytical Transmission Electron Microscopy ◽  
Matrix Composites ◽  
Matrix Microstructure ◽  
Transmission Electron ◽  
The Matrix

From the very beginning of the development of metal matrix composites, (MMC's), electron microscopy has played a major role in their development. Thus, analytical transmission electron microscopy, (ATEM), has been used to characterize and study: the reinforcements in MMC's, interfacial reactions and products that can occur at the interface between the matrix and the reinforcement and the detailed matrix microstructure, particularly the dislocation and grain structure and the precipitation/constituent phases. In this presentation, we will review and discuss the contribution of ATEM to each of these points and describe how it provided necessary information in the design and use of these materials. The presentation will mainly discuss Al-based composites although work from Ti and Mg-based composites will also be presented.

The role of TEM in the development of advanced materials

1990 ◽  
Vol 48 (4) ◽  
pp. 176-177
Author(s):  
M H Loretto
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Advanced Materials ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Matrix ◽  
Scanning Electron

In general the microstructural assessment of advanced materials can be satisfactorily assessed using optical and scanning electron microscopy together with X-ray diffraction. Transmission electron microscopy (TEM) is used only when the scale and nature of the information which can be obtained from TEM is appropriate. The aim of the present article is to highlight some examples of the unique role that TEM has played in the field of structural materials. Four areas will be discussed: metal matrix composites; precipitation in Al-Li based alloys; rapid solidification; intermetallics.In the field of metal-matrix composites one of the most important aspects is nature of the bonding and interaction between the reinforcement and the matrix, and this is an area where the spatial resolution of analytical TEM is required in order to characterise any interaction. The recent work on Ti6A14V/TiC and Ti24All INb/TiC composites has illustrated this very clearly. Even after heat treatments of 50h at 1100°C the TiC appears to be unaffected as assessed by both optical and scanning electron microscopy. Only when TEM is used is it possible to see that there has been any interaction.

Electron Microscopy of Metal-Matrix Composites

1970 ◽  
Vol 28 ◽  
pp. 404-405
Author(s):  
A. Lawley ◽  
M. R. Pinnel ◽  
A. Pattnaik
Keyword(s):  
Electron Microscopy ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Critical Evaluation ◽  
Elastic Behavior ◽  
Matrix Composites ◽  
Directionally Solidified ◽  
Fracture Characteristics ◽  
Broad Program

As part of a broad program on composite materials, the role of the interface on the micromechanics of deformation of metal-matrix composites is being studied. The approach is to correlate elastic behavior, micro and macroyielding, flow, and fracture behavior with associated structural detail (dislocation substructure, fracture characteristics) and stress-state. This provides an understanding of the mode of deformation from an atomistic viewpoint; a critical evaluation can then be made of existing models of composite behavior based on continuum mechanics. This paper covers the electron microscopy (transmission, fractography, scanning microscopy) of two distinct forms of composite material: conventional fiber-reinforced (aluminum-stainless steel) and directionally solidified eutectic alloys (aluminum-copper). In the former, the interface is in the form of a compound and/or solid solution whereas in directionally solidified alloys, the interface consists of a precise crystallographic boundary between the two constituents of the eutectic.

TEM examination of 2014-SiC metal matrix composite

1988 ◽  
Vol 46 ◽  
pp. 726-727
Author(s):  
M. G. Burke ◽  
M. N. Gungor ◽  
P. K. Liaw
Keyword(s):  
Metal Matrix Composite ◽  
Metal Matrix Composites ◽  
Matrix Composite ◽  
Metal Matrix ◽  
Tensile Deformation ◽  
Microstructural Characterization ◽  
Thin Foil ◽  
Matrix Alloy ◽  
Matrix Composites ◽  
Ion Milling

Aluminum-based metal matrix composites offer unique combinations of high specific strength and high stiffness. The improvement in strength and stiffness is related to the particulate reinforcement and the particular matrix alloy chosen. In this way, the metal matrix composite can be tailored for specific materials applications. The microstructural characterization of metal matrix composites is thus important in the development of these materials. In this study, the structure of a p/m 2014-SiC particulate metal matrix composite has been examined after extrusion and tensile deformation.Thin-foil specimens of the 2014-20 vol.% SiCp metal matrix composite were prepared by dimpling to approximately 35 μm prior to ion-milling using a Gatan Dual Ion Mill equipped with a cold stage. These samples were then examined in a Philips 400T TEM/STEM operated at 120 kV. Two material conditions were evaluated: after extrusion (80:1); and after tensile deformation at 250°C.

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