Metallurgy; an introduction to the study of physical metallurgy . ose study of a ternary 50 X 50system would require the examination of —5 = 1,250 alloys—^in itself a stupendous task. In spite of this difficultythe study of ternary systems is now being undertaken vigor-ously, but it must be admitted that the closeness of observa-tions is still far behind that which has been found desirable inthe best investigations of binary systens, so that the results onternary alloys obtained by the majority of workers up to the 124 STUDY OF PHYSICAL METALLURGY present must be regarded rather as preliminary
Metallurgy; an introduction to the study of physical metallurgy . ose study of a ternary 50 X 50system would require the examination of —5 = 1,250 alloys—^in itself a stupendous task. In spite of this difficultythe study of ternary systems is now being undertaken vigor-ously, but it must be admitted that the closeness of observa-tions is still far behind that which has been found desirable inthe best investigations of binary systens, so that the results onternary alloys obtained by the majority of workers up to the 124 STUDY OF PHYSICAL METALLURGY present must be regarded rather as preliminary surveys thanas exhaustive studies. The graphical representation of the constitution of a ternarysystem of alloys is accompUshed by means of a constitutionalmodel in three dimensions in place of the plane constitutionaldiagram which suffices for systems of two components. Wherethe binary diagram is erected upon a single hne as a basis,points along the hne indicating the composition of the mixture,the ternary model is erected upon an area the points in which. Fig. 42.—Triangular Diagram for Plotting the Composition of Ternary Alloys. indicate the composition of the triple mixture. This can bemost conveniently done by employing for the basis of theequihbrium model an equilateral triangle drawn to such ascale that its height is taken as 100. It is a well-knownproperty of such a triangle that the sum of the perpendiculardistances of any point within it from the thiee sides is equal tothe height of the triangle and is, therefore, constant over thewhole area of the triangle. These perpendicular distancesmay thus be used to indicate the percentage composition ofevery alloy of a ternary system. In the triangle ABC of Fig. 42 PHYSICAL PROPERTIES OP ALLOYS 125 perpendiculars have been dropped upon the three sides fromeach of the three corners of the triangle, and each of theseperpendiculars has been divided into ten equal parts. If nowhnes are drawn through each of these divisions
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectmetals, bookyear1922
