A Combined Hot Dip Aluminizing/Laser Alloying Treatment to Produce Iron-Rich Aluminides on Alloy Steel

In the present study, a two-step surface treatment was employed to produce an iron-rich aluminide surface layer on 9Cr1Mo steel. In the first step, the steel specimen was immersed in a 1073 K (800 A degrees C) aluminizing bath for 90 seconds to obtain an Al-rich iron aluminide/Al double layer. Then, the aluminum-rich layer and some portion of the substrate material underneath were melted using a pulsed Nd:YAG laser with different pulse energies in the range of 4 to 8 J. The surface and cross section of the alloyed layers were studied using optical microscopy, scanning electron microscopy, an electron microprobe, and X-ray diffraction analyses. The results showed that after laser remelting of the hot dipped aluminized steel at a pulse energy of 7 J, an integrated layer of FeAl replaced the primary layer. (C) The Minerals, Metals & Materials Society and ASM International 2013