Structure, binary alloys

The aim of the present study is precisely to investigate the thermodynamical properties of an interface when the bulk transition is of first order. We will consider the case of a binary alloy on the fee lattice which orders according to the LI2 (CuaAu type) structure. 

R Bellissent, G. Galli, T. Hyeon, S. Magazu, D. Majolino, P. Migliardo, and K. S. Suslick, Structural properties of amorphous bulk Fe, Co and Fe-Co binary alloys, Physica Scripta, T57 79(1995). 

Langenegger, E. E. and Robinson, F. P. A., Effect of the Polarisation Technique on Dezincihcation Rates and Physical Structure of Dezincihed Zones , Corrosion, 24, 411 (1968) Brooks, W. B., Discussion of the De-alloying Phenomenon , Corrosion, 24, 171 (1968) Pickering, H. W., Volume Diffusion During Anodic Dissolution of a Binary Alloy , J. Electrochem. Soc., 115, 143 (1968)... 

New combined (or binary) alloy sacrificial anodes have been developed . An aluminium anode, for example, might have attached to it a short-life supplementary magnesium anode, or anodes, for quick polarisation of the structure. The overall reduction in structure current requirements is claimed to result in an anode weight saving of 35-50% . 

Bellissent R, Galli G, Hyeon T, Magazu S, Majolino D, Migliardo P, Suslick KS (1995) Structural properties of amorphous bulk Fe, Co, and Fe-Co binary alloys. Phys Scripta 57 79-83, References and further reading may be available for this article. To view references and further read purchase this article... 

Several phase diagrams of binary alloy systems have been shown (see for instance Fig. 2.18) in which the existence of intermediate phases may be noticed. In these systems we have seen the formation of AmB phases, which generally crystallize with structures other than those of the constituent elements, and which have negligible homogeneity ranges. Thermodynamically, the composition of any such phase is variable. In a number of cases, as those exemplified in Fig. 2.19, the possible variation in composition is very small (invariant composition phases or... 

Table 5.6. A selection of formulae and structure types of intermediate phases in the alkali metal binary alloys (CNE coordination number around the A alkali metal).

Table 5.10 summarizes the data relevant to a few selected compositions and more common structure types of the phases formed in the binary alloys of Ca, Sr, Ba, Eu and Yb. Considering the alloys given by the elements of the different groups, some remarks can be made on the following points ... 

Remarks on the crystal chemistry of the alloys of the 3rd group metals. A large number of intermediate phases have been identified in the binary alloys formed by the rare earth metals and actinides with several elements. A short illustrative list is shown in Tables 5.19 and 5.20. Compounds of a few selected rare earth metals and actinides have been considered in order to show some frequent stoichiometries and crystal structure types. The existence of a number of analogies among the different metals considered and the formation of some isostructural series of compounds may be noticed. 

Remarks on the alloy crystal chemistry of the 11th group metals. A selection of the phases formed in the binary alloys of Cu, Ag and Au and of their crystal structures is shown in Tables 5.54a and 5.54b. For a number of these phases, more details (and a classification in terms of Hume-Rothery Phases ) are given in 4.4.5 and in Table 4.5 (structure types, valence electron concentration, etc.). Table 5.54a and 5.54b show the formation of several phases having a high content... 

Electrodeposited binary alloys may or may not be the same in phase structure as those formed metallurgically. By way of illustration, we note that in the case of brass (Cu-Zn alloy), x-ray examination reveals that apart from the superstructure of... 

Let us take the example of a simple commercial alloy such as Ti-6AI-4V. This is the most popular structural Ti alloy used worldwide. Essentially one would need to consider Ti-AI, Ti-V and Al-V binary interactions and Ti-Al-V ternary interactions. Unfortunately, although called Ti-6AI-4V, this alloy also contains small amounts of O, C, N and Fe and it therefore exists in the multi-component space within the Ti-Al-V-O-C-N-Fe system. There are then 21 potential binary... 

The properties of some rare-earth binary alloys with platinum group metals are also important in view of the role they can play in the chain of preparing ternary hydrides. Many of the alloys of the series R-M, where R is a rare earth element and M is a Group VIIIB metal, have been investigated structurally and magnetically. The alloys with iridium all have cubic structures, whereas those... 

Small particles of binary alloys have been investigated in detail in static EXAFS experiments, but if information about the dynamic behavior of the alloy composition and the segregation phenomena is desired, time-resolved combined EXAFS/XRD studies are necessary. Figure 18 shows the atomic structure of a small binary particle of a Ni-Au alloy as predicted from Monte Carlo simulations (60). Ni and Au do not form a miscible alloy in the bulk but can form a stable alloy at the surface. The structural and chemical changes that occur when such particles are exposed to different... 

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