A eutectic mixture results when two components solidify simultaneously at a definite temperature.
Such a mixture has a constant melting point and because of this and also because both solid and liquid phases have the same composition, eutectic mixtures were formerly looked upon as compounds.
For an alloy of the composition of the eutectic itself there is no arrest until the eutectic temperature is reached, at which the whole solidifies without change of temperature.
The alloy corresponding to the cryohydrate, possessing the lowest melting point, is called the eutectic alloy, as it is most easily cast and worked.
When the eutectic temperature is reached there is a second F.
The higher eutectic D may correspond to a complex of solid thallium and the compound; but the possible existence of solid solutions makes further investigation necessary here.
Here, the large dark masses are the silver or silver-rich substance that crystallized above the eutectic temperature, and the more minute black and white complex represents the eutectic.
The mixture C has a lower freezing or melting point than that of any other mixture; it is called the eutectic mixture.
There are thus two eutectic alloys B and D, and the alloys with compositions between B and D have higher melting-points.
It is probable that all the alloys of compositions between B and D, when they begin to solidify, deposit crystals of the compound; the lower eutectic B probably corresponds to a solid complex of mercury and the compound.
It is evident that every mixture except the eutectic mixture C will have two halts in its cooling, and that its solidification will take place in two stages.
The horizontal line through the eutectic point gives the second halt in cooling, due to the simultaneous formation of lead crystals and tin crystals.
The two sloping lines cutting at theeutectic point are the freezing-point curves of alloys that, when they begin to solidify, deposit crystals of lead and tin respectively.
The analogy between the breaking up of a solid solution on cooling and the formation of a eutectic is obvious.
The pearlite when highly magnified somewhat resembles the lead-tin eutectic of fig.
If the initial composition of the magma is represented by a point between the two eutectic points, orthoclase will separate first.
It is, however, a metastable eutectic point, for it lies in the region of supersaturation with respect to the heptahydrate; and it can be realized only because of the fact that the latter hydrate is not readily formed.
Suppose the ternary eutectic curves projected on a plane parallel to the face of the prism containing B and C, i.
The relationship between initial composition of solution and the duration of constant temperature at the eutectic point is represented by the curve a'c'b' (Fig.
After this the temperature again falls, until it again remains constant at the eutectic point c.
Bc, and also, in case of hyper-eutectic iron, in the passage through region 3.
Both the primary and eutectic austenite have changed in cooling into a mixture of pearlite and pro-eutectoid cementite, too fine to be distinguished here.
Second, the very genesis of so bulky a substance as the primary and eutectic graphite while the metal is solidifying (fig.
This formation of cementite through the rejection of carbon by both the primary and the eutectic austenite continues quite as in the case of 1.
B), increases in amount until, when the carbon-content reaches the eutectic ratio, 4.
If it differs widely from the eutectic in composition, then when solidified it consists of only a small quantity of eutectic and a very large quantity of the excess metal.
At this point selection ceases; the remaining molten metal freezes as a whole, and in freezing splits up into a conglomerate eutectic of (1) austenite of about 2.
The constitution of hypo-eutectic white or cementitiferous cast iron (washed metal), W.
A "eutectoid" is to such a transformation in solid metal what a eutectic is to freezing proper.
Lead-tin solders are eutectic alloys--that is, they are examples of the phenomenon of a combination of two metals melting at a temperature lower than one of them would if melted separately.
This, therefore, is the composition of the eutectic alloy, and it finds its place naturally on the curve given in Fig.
Although many fusible alloys have been long known, I believe no true eutectic metallic alloy had been studied until Dr.
This is the only case in which a eutectic mixture is possible, and it is, of course, found at the lowest point of the curve.
From this diagram we should be led to expect a eutectic mixture, since the curve dips below a horizontal line passing through the melting-point of the more fusible of its constituents.
It will be seen at once by this definition that the temperature of liquefaction of a eutectic substance is lower than the temperature of liquefaction of either or any of the constituents of the mixture.
The characters of this particular solution are thus closely analogous to those of the eutectic mixtures described above.
The final solid thus consists of blebs of silver scattered through a fine groundmass of eutectic mixture of silver and copper.
The final solid thus consists of large particles of sodium chloride dispersed through a fine groundmass consisting of eutectic mixture of sodium chloride and ice.
The eutectic mixture of iron (or ferrite) and cementite is known as pearlite.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "eutectic" in a variety of sentences. We hope that you will now be able to make sentences using this word.
