Alloy single-phase

Special Alloys. AHoys of tin with the rater metals, such as niobium, titanium, and 2kconium, have been developed. The single-phase alloy Nb Sn [12035-04-0] has the highest transition temperature of any known superconductor (18 K) and appears to keep its superconductivity in magnetic... 

Single-Phase Alloys. Copper—tin—zinc-lead alloys, tin bronzes, and the leaded tin bronzes have a narrow range of properties, namely,... 

In single phase alloys which are A1 rich, the SISF energy is high and thus the difference between planar and non-planar cores of the superdislocations will not be large. Hence, even if the sessile form is energetically favored, the superdislocations may possess metastable planar... 

Corrosion of Impure Metals and Single-phase Alloys... 

In contrast, the selective dissolution or leaching-out by corrosion of one component of a single-phase alloy is of considerable practical importance. The most common example of this phenomenon, which is also referred to as parting , is dezincification, i.e. the selective removal of zinc from brass (see Section 1.6). Similar phenomena are observed in other binary copper-base alloys, notably Cu-Al, as well as in other alloy systems. 

Figure 57.16. The comparison of A1 leachability for the casted single-phase alloy powders, the casted multiphase alloy block and CA53. The CA53 was activated at it with 10 wt.% NaOH and its A1 content was determined by x-ray. The other casted alloys were activated at it with 20 wt.% NaOH and their A1 contents were ascertained by SEM EDX.

Alloys are classified broadly in two categories, single-phase alloys and multiple-phase alloys. A phase is characterized by having a homogeneous composition on a macroscopic scale, a uniform structure, and a distinct interface with any other phase present. The coexistence of ice, liquid water, and water vapor meets the criteria of composition and structure, but distinct boundaries exist between the states, so there are three phases present. When liquid metals are combined, there is usually some limit to the solubility of one metal in another. An exception to this is the liquid mixture of copper and nickel, which forms a solution of any composition between pure copper and pure nickel. The molten metals are completely miscible. When the mixture is cooled, a solid results that has a random distribution of both types of atoms in an fee structure. This single solid phase thus constitutes a solid solution of the two metals, so it meets the criteria for a single-phase alloy. 

The points of these segments represent the AmixG of two-phase alloys. In the composition range between the maximum and the spinodal (xs) a two-phase alloy, such as a mixture xul + xu2, has therefore an overall free energy lower than that of any single-phase alloy of an intermediate composition, which is therefore unstable. 

This section focuses on the modification of epoxy resins by blending with acrylonitrile butadiene (nitrile) resins. These are true alloyed blends since the nitrile rubber usually contains no groups that are normally reactive with epoxy groups. The nitrile molecules and the epoxy molecules intermingle as a blend to provide a single-phase alloy. If a large elastomer concentration is used, no phase separation will occur to form precipitates. 

Alloys are classified broadly in two categories, single-phase alloys and multiple-phase alloys. A phase is characterized by having a homogeneous composition on a macroscopic scale, a uniform structure, and a distinct interface with any other phase present. The coexistence of ice, liquid water, and water vapor meets the criteria of composition and structure, and distinct boundaries exist between the states so there are three phases present. 

In the case of the single phase alloy Smo.5Ybo.5Cu2Ge2 the NMR signal due to copper was not detected and the resonance line broadening beyond the point of detection due to spatial fluctuation of EFG at the copper nuclei explains the reason why rare earths in EuCu2Si2 and YbCu2Si2 appear identical to the copper nuclei. 

The key to the interpretation of the powder patterns of alloys is the fact that each phase produces its own pattern independently of the presence or absence of any other phase. Thus a single-phase alloy produces a single pattern while the pattern of a two-phase alloy consists of two superimposed patterns, one due to each phase. 

Rousset and co-workers [199] prepared Au/Zr02 catalysts simply via the oxidation of a Zro.sAuo.s single-phase alloy in air at 293K. Authors think that this solvent-free method, which requires neither costly post-S3mthetic heat treatments nor the costly set-ups involved in the physical routes of preparation, is a good and alternative route in terms of cost and environment and could be suitable method for the preparation of active gold catalysts on a large scale [199]. 

If the two metals that form the alloy are insoluble in one another, then they will exist as two separate phases, often in alternate layers such as observed in tin-lead alloys or cast irons, where the carbon is often found as minute tadpole like shape (flakes) adjacent to the pure iron. These types of two-phase alloys are extremely difficult if not impossible to shape by hot or cold working. Fortunately, these alloys have a melting point well below that of the parent metals and are very suitable to shape by casting into moulds. This is the reason why iron 4.5% carbon alloys were called cast irons. These alloys have two important limitations in that first, they are very brittle when subjected to impact loads, and second, their corrosion resistance is inferior to pure metals or single-phase alloys. 

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