Phase transformations during isochronal annealing of Fe40Ni40B20 glass

An investigation is made of structural changes which occur during isochronal annealing of amorphous Fe40Ni40B20 alloy in the temperature interval 20 to 1000 °C. Parallel to X-ray investigations, differential thermal analysis and resistometric and microhardness studies are performed. The results can be summarized as follows: the glass transition temperature Tg is around 272 °C, the crystallization starts at Tc = 393 °C and the first crystalline phase appearing (Fe, Ni)3B is annealed out at higher temperatures and only (Fe, Ni) austenite remains. The boron component seems to diffuse, in amorphous form on the grain boundaries and/or at the surface of the samples.