Elevated temperature wear behaviors of a Co?Mo?Si ternary metal silicide alloy

A noval wear resistant Moss-toughened Mo2Ni3Si metal silicide alloys was designed and manufactured with the commercial Mo, Ni and Si powders. Wear resistance of the alloys was evaluated under dry-sliding wear test condition at room temperature. Results show that the alloys have excellent wear resistance and tribological compatibility coupling with conventional metallic materials due to the high hardness and strong atomic bonds of the ternary metal silicide Mo2Ni3Si with MgZn2 type Laves crystal structure.

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Evidence for a shear mechanism for the precipitation of γ-zirconium hydride in zirconium

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010011043x ◽

1978 ◽

Vol 36 (1) ◽

pp. 658-659

Author(s):

G.J.C. Carpenter

Keyword(s):

Elevated Temperature ◽

Strain Field ◽

Zirconium Hydride ◽

Zirconium Atom ◽

Atom Diffusion ◽

Solvus Temperature ◽

Hexagonal Close Packed ◽

Partial Dislocations ◽

The Face

In zirconium-hydrogen alloys, rapid cooling from an elevated temperature causes precipitation of the face-centred tetragonal (fct) phase, γZrH, in the form of needles, parallel to the close-packed <1120>zr directions (1). With low hydrogen concentrations, the hydride solvus is sufficiently low that zirconium atom diffusion cannot occur. For example, with 6 μg/g hydrogen, the solvus temperature is approximately 370 K (2), at which only the hydrogen diffuses readily. Shears are therefore necessary to produce the crystallographic transformation from hexagonal close-packed (hep) zirconium to fct hydride.The simplest mechanism for the transformation is the passage of Shockley partial dislocations having Burgers vectors (b) of the type 1/3<0110> on every second (0001)Zr plane. If the partial dislocations are in the form of loops with the same b, the crosssection of a hydride precipitate will be as shown in fig.1. A consequence of this type of transformation is that a cumulative shear, S, is produced that leads to a strain field in the surrounding zirconium matrix, as illustrated in fig.2a.

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Digital image processing methods applied to the study of annealing time on semiconductor-metal eutectic composites

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100106302 ◽

1988 ◽

Vol 46 ◽

pp. 848-849

Author(s):

J. Hefter

Keyword(s):

Image Processing ◽

Digital Image Processing ◽

Digital Image ◽

Electronic Device ◽

Processing System ◽

Average Diameter ◽

Eutectic Solidification ◽

Metal Silicide ◽

The Matrix ◽

Microscopic Studies

Semiconductor-metal composites, formed by the eutectic solidification of silicon and a metal silicide have been under investigation for some time for a number of electronic device applications. This composite system is comprised of a silicon matrix containing extended metal-silicide rod-shaped structures aligned in parallel throughout the material. The average diameter of such a rod in a typical system is about 1 μm. Thus, characterization of the rod morphology by electron microscope methods is necessitated.The types of morphometric information that may be obtained from such microscopic studies coupled with image processing are (i) the area fraction of rods in the matrix, (ii) the average rod diameter, (iii) an average circularity (roundness), and (iv) the number density (Nd;rods/cm2). To acquire electron images of these materials, a digital image processing system (Tracor Northern 5500/5600) attached to a JEOL JXA-840 analytical SEM has been used.

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