Two-phase ternary Fe-Ti-Si alloys with Si contents from 2 to 16 at.% and Ti contents from 2 to 28 at.% were studied with respect to room temperature hardness, fracture strain and yield stress at room and higher temperatures up to 1150°C. In addition oxidation was checked at temperatures between 400 and 1150°C. The alloys are strengthened by precipitation of the stable Laves phase (Fe,Si)2Ti which is a hard and brittle intermetallic phase. The yield stress as well as the brittle-to-ductile transition temperature (BDTT) increase with increasing Ti content. Yield stresses up to about 1400 MPa and BDTT between 100°C and 600°C with fracture strains of the order of 1 % below BDTT were achieved. The observed short-term oxidation performance at temperatures up to 1150°C compares favourably with that of Fe-AI alloys with high AI contents.

Phase equilibria in the Fe-Mg-Si system have been determined experimentally at 800 and 1 000 8C using alloys of fixed composition and diffusion couples. Besides the phases that occur in the binary systems no additional phases were observed. However, Fe 5 Si 3 , the only phase that shows a marked solid solubility for the third component, is stabilised by the addition of Mg to lower temperatures than in the binary Fe-Si system, thus forming a ternary composition at 800 8C. A complete isothermal section has been set up for 800 8C, while only selected phase equilibria were determined at 1 000 8C.