Crystalline Wires Research Articles

Solidification phenomena in formation process of rapidly solidified metallic wire

Rapidly solidified crystalline wires were produced by the in-rotating-water spinning method. The solidification structure was microscopically observed and the mode of solidification was theoretically analysed. Two kinds of solidification structure were observed: a fine dendritic structure and a radially growing structure. The formation of these structures is explained by discussing the nucleation phenomena and the crystal growth.

Mechanisms of cone formation by ion bombardment

In this paper, cone formation due to the sputtering of CuAg alloy and cylindrical geometry solids (amorphous and crystalline wires) bombarded by Ar + ions has been considered. Two basic mechanisms which apply to the bombarded alloy surface are: different sputtering rate of alloy components and different defect concentration and stopping power along the ion range in the crystal. The results also show previously reported mechanisms of cone formation such as a masking effect of impurity atoms and the angular dependence of sputtering.

Analysis of ion bombarded cylindrical geometry solids

An experimental technique was applied to develop the topographic evolution of cylindrical geometry solids produced Ar + ion bombardment. The cross-section profile variations of amorphous and crystaline cylinders were examined as a function of the sputtering rate and bombardment dose. Circular cross-section contour changes firstly to a rounded wedge and then to the straight sided wedge. This cross-section profile is obtained on amorphous and crystalline wires, although on the metal wires, because of the influence of the crystal structure, it was difficult to follow the macroscopic topographic contours by scanning electron microscopy.

Studies in the cold drawing of Pd77.5Cu6Si16.5 metallic glass and 316 stainless steel crystalline wires

The stress necessary to draw Pd77.5Cu6Si16.5 metallic glass wires has been measured using a tensile machine, and compared with that of 316 stainless steel crystalline wires. To assess the elastic back-pull of a drawn material, variable static back-stresses have been loaded on a drawing wire. In the case of the metallic glass wires, the draw stress, σd, under different applied back-pulls, σab, increases linearly with the reduction in area, Ra, up to 23% and then increases less rapidly. This tendency of the curve σd versus Ra is also the same in 316 crystalline wires. On the other hand, the elastic back-pull of the glassy wires is 2.05 kg mm−2 at zero applied back-pull and then decreases monotonically with σab, while that of the 316 crystalline wires is 6.62 kg mm−2 at σab=0 and decreases linearly with the increase in σab. The empirical maximum reduction in Pd77.5Cu6Si16.5 metallic glass wire for one-pass drawing is measured to be 40% at σab=0 and it then decreases with increasing σab. The resultant curves of drawing stress versus reduction in area are discussed in the light of plastic theory. The theoretical curves calculated under the assumption of small strain-hardening fits quite well with the experimental curves of Pd77.5Cu6Si16.5 glassy wires.