3.58 shows the developed view, i.e., projection of liquidus on the base. 3.57 (a) illustrates the three dimensional view of the ternary diagram, whereas Fig. Each two metals form binary eutectic, being illustrated on each side of the triangle, but all three form a ternary eutectic. It is a system in which all three metals are completely insoluble in each other in solid state. 3.56 illustrates the ternary diagram for a system with complete solid solubility with three methods of representing in two dimensions. The vertical sections also show the temperatures at which the various phase changes occur.įig. However, vertical sections are quite valuable in showing the phases that are present in an alloy during equilibrium cooling and heating. The tie lines do not usually lie in the plane of a vertical section, and thus cannot be used to obtain amounts and compositions at that temperature. 3.56 (c), though resemble binary diagrams (composition v temperature), but lack an important characteristic. (iii) Vertical Sections (Isopleths), either from one corner of the space diagram or parallel to one side of the space diagram, Fig. These diagrams generally provide the most satisfactory means for recording ternary equilibrium in two dimensions. It is useful in predicting the phases, their amounts and compositions at that temperature.
Thus, isothermal (horizontal) sections cut through the three dimensional composition-temperature diagram at a series of temperatures can be obtained. Simple composition triangles at constant temperature (pressure is already constant) are important in determining the phase constitution of alloy, Fig. Liquidus plot also gives the identity of the primary phase that forms during solidification for any given composition. Thus, freezing temperature of the material can be predicted. Normally, liquidus temperatures can be plotted as isothermal contours, Fig. It is a projection of the ‘plan’ of three- dimensional diagram, Fig. Three dimensional diagrams is not convenient for making detailed phase analysis.īut, the information can be presented in two dimensions by any of the several methods: