Composite Foil Research Articles

Transmission Electron Microscopy of Interfacial Areas in Metal-Matrix Composites*

Microtechniques of selected-area transmission electron microscopy have been developed for the study of interfacial areas in a high- strength aluminum alloy reinforced with stainless-steel wires. The specimen-preparation procedures are described and the conditions necessary for the successful production of useful areas of trans mission progressively nearer the interface in the composite foils are discussed. Dislocation arrangements in the aluminum alloy matrix of a composite subjected to fatigue loading have been ob served as a function of the distance from the filament-matrix interface. The dislocation density was not appreciably affected by the presence of the filament-matrix interface to within 25 microns of the interface. The results demonstrate the potential usefulness of such studies to the development of improved design criteria through a better understanding of the micromechanisms of com posite behavior.

Ion energies in the plasma produced by a high power laser

A Q switched ruby laser focussed onto a metal foil produces ions with high energy. Ions from different pure foils were found to have the same energy distribution, whereas ions from a composite foil all have the same velocity distribution.

Rigid Packaging Materials for Consumer Goods

THE PACKAGING MATERIALS INDUSTRY is probably one of the most challenging for an analyst to study. Composed of many companies, it includes some of the blue chips of American industry. New developments and changes are taking place daily that can alter greatly the fortunes of the companies within the industry. Competitiveness in packaging has accelerated in recent years. Diversified corporations such as American Can, Continental Can and Owens-Illinois each have several divisions which produce varied types of packaging. In many instances, divisions vie for the same markets. Customer demand for outstanding packaging innovation has increased competition and spurred the rapid development of newer and better packaging materials. The rigid container segment of the packaging industry, an important factor in consumer goods, has held my attention for many years. The battle between the glass container and its long time foe, the metal can, has been impressive. A third adversary, the rigid plastic container, has initiated a challenge to both glass and metal containers. The next decade will probably see the industry moving at so rapid a pace, that it will be extremely difficult to keep abreast of it. Consideration of the varied developments that have taken place in recent years and the trends that are currently under way should aid us in distinguishing the areas which offer the greatest opportunity for investment. The analyst, to gain an objective appraisal of this multi-faceted industry, as with any particular company, must learn what factors are of greatest influence and to what degree these factors will affect future results. The markets served, the pace of expansion or contraction, motivation for particular trends, competitive materials, the product or company with the largest share, and the reasons for any hold on a market are paramount in any appraisal. Some of us can still remember when automotive motor oil was sold in narrow neck glass containers. The development of a convenient pouring spout for metal cans was one of the major factors influencing the switch to metal containers in the post-war era. More recently, aluminum cans have gained acceptance. In the past three years, the composite fiber foil can has made significant strides, and will be in direct and fierce competition with the most recent entry, the plastic container. Thus, in a span of thirty years, we have had five different containers for the automotive oil market alone. Over the next thirty years, changes in packaging materials will be accelerated as manufacturers demand better, lower cost containers, and apply greater emphasis on containers as advertising mediums to merchandise products.

Photon Emission from Irradiated Dielectric Slabs

In this paper a simple derivation is given of the distribution of photons emitted when an energetic charged particle passes through a thin layer of dielectric material. This derivation emphasizes the individual microscopic events which occur during such a process. The distribution function is shown to agree with that obtainable from the transition radiation theory of Frank and Ginzburg and from the plasmon decay theory of Ferrell for the case of a thin foil. The special case of a double foil bounded by vacuum is considered in detail, and a general formula is found for the photon distribution function. An approximation analogous to that of Born's in quantum mechanics is developed to treat the case of a general composite foil whose thickness is small compared with λ but which may be large compared with vλ/c, where λ is the wavelength of the light emitted and v is the speed of the charged particle.

The Nuclear Scattering of 0.4 and 0.5 MeV Electrons in Composite Aluminium-Uranium Foils

The Nuclear Scattering of 0.4 and 0.5 MeV Electrons in Composite Aluminium-Uranium Foils

The Scattering of 50-Kilovolt Electrons by Aluminum

Apparatus is described for scattering electrons with thin foils and measuring the intensity of scattering in a narrow pencil making any angle from 30\ifmmode^\circ\else\textdegree\fi{} to 120\ifmmode^\circ\else\textdegree\fi{} with the direction of incidence. Electrons with energies below 95 percent of the energy on incidence are excluded by a retarding voltage. The theory of nearly single scattering is discussed, and a general expression is found for the error introduced by slight plural scattering. In the case of Rutherford scattering this expression gives for the fractional error the value ${\ensuremath{\epsilon}}^{2}{{csc}^{2}(\frac{\ensuremath{\theta}}{2})\ensuremath{-}\frac{1}{2}}$ where $\ensuremath{\theta}$ is the angle at which scattering is measured and ${\ensuremath{\epsilon}}^{2}$ is the mean square deflection of particles traversing in the foil the same length of path as those scattered at the angle $\ensuremath{\theta}$. The relation of this result to Wentzel's criterion is shown. Electrons accelerated by 50 kv were scattered by thin composite foils of Al on collodion. A difference was found, though not explained, between the intensities of scattering at 90\ifmmode^\circ\else\textdegree\fi{} on the two sides of the foil, which was inclined at 45\ifmmode^\circ\else\textdegree\fi{} to the direction of incidence. With allowance made for this asymmetry in comparing the scattering at angles above and below 90\ifmmode^\circ\else\textdegree\fi{}, relative intensities at angles from 30\ifmmode^\circ\else\textdegree\fi{} to 120\ifmmode^\circ\else\textdegree\fi{} were within 5 percent of those predicted by Mott. Comparison of the observed and predicted absolute intensities of the scattering from Al was subject to an uncertainty of about 20 percent, principally in the determination of the thickness of the Al film. Within this uncertainty, the observation agreed with the prediction. If the actual scattering differs from the predicted, it appears from these observations to be more probably less than greater.