Nature of boron in α-iron

Internal friction measurements were carried out on iron-boron and iron-nickel-boron alloy specimens, in order to define the nature of the boron solid solution in α-iron. An internal friction peak corresponding to a small amount of boron in α-iron was observed. Referring to the lattice parameter measurements, and the diffusion experiment, it can be concluded that boron atoms occupy both substitutional and interstitial positions. The concept of dissociative diffusion explains well the diffusion mechanism of boron in α-iron. The relaxation time of the jump of an interstitial boron atom is shown to be 10~13 exp ( 13000/ RT) sec.