Dynamic Compaction of Al Alloys

1983 ◽  
Vol 28 ◽  
Author(s):  
J.W. Sears ◽  
B.C. Muddle ◽  
H.L. Fraser

ABSTRACTPowders of Al alloy 7091 have been consolidated by means of dynamic compaction. The dependence of density and hardness on projectile velocity has been determined. The resulting as-compacted material has been characterized using analytical transmission electron microscopy and evidence of interparticle melting observed. The microstructural responseof the compacted material to heat treatment at 523 and 723°K has been investigated.

2008 ◽  
Vol 403 ◽  
pp. 103-106
Author(s):  
L.K.L. Falk ◽  
Yvonne Menke ◽  
Stuart Hampshire

This paper is focussed on the development of microstructure during crystallisation heat treatment of B-phase parent glasses with composition (e/o) 35R:45Si:20Al:83O:17N, where R = Er, Yb, Y or a mixture of Y and Yb. Extensive high resolution analytical transmission electron microscopy has shown that the lenticular B-phase crystals take up a substantial range of composition. The element R is always clearly anti-correlated with the Si, and a larger R3+ cation radius moves the composition range to lower R contents. It is suggested that a locally increased density in the bi-dimensional network of randomly oriented (Si,Al)(O,N)4 tetrahedra is associated with an increased density of vacancies in the R3+ cation lattice.


Author(s):  
George Guthrie ◽  
David Veblen

The nature of a geologic fluid can often be inferred from fluid-filled cavities (generally <100 μm in size) that are trapped during the growth of a mineral. A variety of techniques enables the fluids and daughter crystals (any solid precipitated from the trapped fluid) to be identified from cavities greater than a few micrometers. Many minerals, however, contain fluid inclusions smaller than a micrometer. Though inclusions this small are difficult or impossible to study by conventional techniques, they are ideally suited for study by analytical/ transmission electron microscopy (A/TEM) and electron diffraction. We have used this technique to study fluid inclusions and daughter crystals in diamond and feldspar.Inclusion-rich samples of diamond and feldspar were ion-thinned to electron transparency and examined with a Philips 420T electron microscope (120 keV) equipped with an EDAX beryllium-windowed energy dispersive spectrometer. Thin edges of the sample were perforated in areas that appeared in light microscopy to be populated densely with inclusions. In a few cases, the perforations were bound polygonal sides to which crystals (structurally and compositionally different from the host mineral) were attached (Figure 1).


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