Metallurgy; an introduction to the study of physical metallurgy . erence that the substance which now separates in the purestate, when freezing commences, is pure B where it was formerlypure A. The composition of the residual Uquid and thetemperature of final sohdification remain unaltered until thewhole mass of metal consists of pure B, which, of course, againBolidifies in the manner already described for pure metals. THERMAL STUDY OP METALS AND ALLOYS 91 This entire process or group of processes, although somewhatcompUcated when thus verbally described, is very readilyrepresented by the aid
Metallurgy; an introduction to the study of physical metallurgy . erence that the substance which now separates in the purestate, when freezing commences, is pure B where it was formerlypure A. The composition of the residual Uquid and thetemperature of final sohdification remain unaltered until thewhole mass of metal consists of pure B, which, of course, againBolidifies in the manner already described for pure metals. THERMAL STUDY OP METALS AND ALLOYS 91 This entire process or group of processes, although somewhatcompUcated when thus verbally described, is very readilyrepresented by the aid of a diagram. If we plot as abscissaethe percentage compositions of a series of alloys, and then,using temperature as ordinate, insert the points correspondingto the beginning of freezing in each alloy and also the pointscorresponding to the freezing of the residual metal or eutectio,we obtain a diagram which represents the entire set of pro-cesses in a simple manner. Such a diagram is shown for theimaginary case of two metals perfectly insoluble in one another. FiO. 30.—Ideal Equilibrium (Constitutional) Diagram of a simpleBinary Eutectilerous System. in the soUd state, in Fig. 30. Such a diagram is in reality asummary of the indications of the cooling-curves of all thealloys of the system, and from the diagram the nature of thecooUng-curve of any of these alloys can be readily relationship is indicated in the diagram (Eig. 31) wherethe cooUng-curves of some of the alloys are shown, ti lookingat this diagram it must be remembered that the peaks of the cooUng-curves really lie in a plane at right-angles to thatof the diagram, since the co-ordinates of the cooling-curve aretemperature and time, while those of the diagram proper aretemperature and composition of the alloy. The diagram 92 STUDY OF PHYSICAL METALLURGY shown in Fig. 30, while thus representing a summary of a wholeseries of cooling-curves, has a further meaning, since it alsoserves as a species of map
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectmetals, bookyear1922
