Eutectic features often appear in parts of more complex phase diagrams, as shown in the iron-uranium diagram of Fig. 8.14. If the diagram is divided into three parts at 1/3 and 6/7 mole fraction uranium, the result is two simple eutectic diagrams and a more complex diagram.
The Fe-rich side resembles Fig. 8.11 with two added features. The first is the number of phases of the pure components. The left hand ordinate of Fig. 8.14 makes provision for three crystallographic modifications of iron: The a phase (designated as aFe) is stable up to 912oC; yFe exists in the range 912 < T < 1394oC; the SFe phase is the equilibrium form from 1394oC to the melting point. The aFe/yFe and the yFe/SFe transitions are indicated by horizontal lines at 912 and 1394oC. Uranium is completely insoluble in all three crystal forms of iron. The eutectic point is at 17 mole percent uranium and 1080oC.
The other feature that distinguishes the Fe-rich portion of the iron-uranium phase diagram from the gold-silicon diagram of Fig. 8.11 is the right hand border at xU = 0.333. In the Au-Si system, the eutectic is bounded on the right by pure Si. The left-hand eutectic portion of the Fe-U diagram, on the other hand, has an intermetallic compound,
Was this article helpful?
Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.