Homogeneous alloy

The nature of alloys. Homogeneous and heterogeneous alloys. Solid solutions, intermetallic compounds. The phase rule, P - - P = C 2 number of phases, variance, number of components of a system in equilibrium triple point. Phase diagrams of binary systems eutectic mixture eutectic point. The systems As-Pb, Pb-Sn, Ag-Au, Ag-Sr. 

Tungsten addition as scheelite permits rapid attainment of alloy homogeneity at a recovery of 94%. The costs are significantly lower but the addition is limited to 5% W in steel. Higher amounts increase the slag volume and thus decrease the recovery. 

Metal Alloy Homogeneous mixture of two or more metals. 

What is the lowest temperature at which an alloy of silver and strontium can remain liquid What is the composition of this alloy Is the solid alloy homogeneous or heterogeneous Does it have a sharp melting point ... 

The metals and alloys that were originally used in the medical environment were selected on the basis of their strength and ductility although their original genesis may have been for a totally different purpose. To surmount problems due to corrosion under saline conditions alloys (homogeneous mixtures of the metallic elements at the atomic level) have been developed to render materials passive to corrosion. Another method is to promote the formation of an adherent oxide layer, often by acid treatment of the metallic phase. Both methods are currently used. 

Runnals [85] patented a method for making americium-aluminum alloys in which a mixture of aluminum metal and an americium halide is heated in a vacuum of 10 torr at 700-1200°C until the americium is reduced and alloyed. Homogeneous ameridum-aluminum alloys suitable for irradiation of americium can be prepared by reaction of aluminum, Am02, and NajAlF (cryolite) at 1100-1200°C [86]. d-Plutonium and jS-americium form a continuous series of fee solid solutions that are stable at room temperature in the composition range from about 6 to 80 at % americium [294]. Other alloys and intermetallic compounds are listed in Table 8.3. 

Heat-treatable alloy Homogenization Hot rolled temper (F)... 

The stabilizing influence of boron atoms in the octahedral sites of the perovskite metal host lattice structure was investigated by Holleck (1977) for ScIr3B,, a = 3.999(2), Pm3m, Cu3Au-type, by X-ray and metallographic analysis of arc melted alloys, homogenized at 1300°C. 

In order to clearly differentiate between the contributions from solid solution, disorder-order and precipitation strengthening contributions in such alloys, homogenized (i.e., solution annealed) and quickly quenched samples need to be investigated and compared with subsequently aged samples. 

An alloy ideally should be homogeneous, but in practise it can contain segregations, for example hard alpha in titanium. Beeause of their different mechanieal properties sueh segregations can be the origin of eracks when the component is operated near to its temperature and stress limits. 

Homogeneous alloys have a single glass transition temperature which is determined by the ratio of the components. The physical properties of these alloys are averages based on the composition of the alloy. 

These reactions are usehil for the preparation of homogeneous difunctional initiators from a-methylstyrene in polar solvents such as tetrahydrofuran. Because of the low ceiling temperature of a-methylstyrene (T = 61° C) (26), dimers or tetramers can be formed depending on the alkaU metal system, temperature, and concentration. Thus the reduction of a-methylstyrene by sodium potassium alloy produces the dimeric dianionic initiators in THF (27), while the reduction with sodium metal forms the tetrameric dianions as the main products (28). The stmctures of the dimer and tetramer correspond to initial tail-to-tail addition to form the most stable dianion as shown in equations 6 and 7 (28). 

Not all elements of the industrial thermocouple need to be wine. For example, if a copper pipe contains a flowing fluid whose temperature is to be measured, a constantan wine attached to the pipe will form a T, or copper—constantan, thermocouple. Such arrangements ate difficult to caUbrate and requite full understanding of the possible inherent problems. For example, is the copper pipe fully annealed Homogeneous Pure, or an alloy Many ingenious solutions to specific measurement problems ate given in Reference 6. 

Multiple-arc melting for a minimum of two melts is conventionally used to ensure a homogeneous ingot. Although conventional arc-melt practice involves a negative electrode, improved alloying is achieved with a positive electrode for at least one of the several melts and usually the first melt. 

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