STRUCTURE OF IRON ALLOYS.

The constitution of iron-rich alloys of iron with indium, germanium, molybdenum, tungsten, and tantalum has been investigated by a combination of thermal analysis, dilatometry, X-ray diffraction, and microscopic methods. Dilatometric methods have been used to study the equilibria in binary alloys of iron with molybdenum, ruthenium, and rhodium, and the lattice spacings of these alloys have been determined at room and at high temperatures. The lattice distortions produced are clearly related to the positions of the solute elements in the Periodic Table, but the behavior of manganese is anomalous. The Fe-In system gives rise to a range of partial immiscibility in the liquid state, and resembles in this respect the Fe-Sn system. The Fe-Ge system is of the lambda-loop type. The Fe-Mo system is of great interest it is of the lambda-loop type and involves a Laves phase, Fe2Mo is only stable at low temperatures, and the R phase is stable only at high temperatures, which is the first binary iron alloy phase to be established with this structure. The relations between these structures are discussed. The Fe-W system shows analogous lambda- and mu-phases.