Microstructure and Properties of Ferrous Substrates Laser-Alloyed with Boride Particles

摘要

Laser alloying of ferrous substrates with borides is a well suited method to improve the surface properties of the substrate material. In this sutdy Ni_2B, CrB or CrB_2 powder was injected into the molten bath on the iron or steel substrate surface created by irradiation with a CW-CO_2 laser. Characterization of the surface-alloyed layers reveal microstructural differences due to the used boride powder. Ni_2B laser-alloyed Armco iron reveals the formation of an off-eutectic microstructure, which consists of Fe(Ni) dendrites and Fe(Ni) and (Fe,Ni)_3B lamellae. Depending on the amount of injected and dissolved Ni_2B particles the Fe(Ni) phase solidifies in the bcc or fcc structure.