Surface modification of low carbon steel via Al-rich overlayer cladding

Low oxidation resistance of low carbon steel restricts the applications of these materials at elevated temperature. Due to the high corrosion and oxidation resistance of Al base alloys، in this research low carbon steel substrate was subjected to the weld cladding with using Al-rich overlayer. Microstructural studies by using optical and scanning electron microscopes indicated the formation of needle-like Al-rich intermetallic with nearly uniform distribution in the Al clad overlayer. This clad overlayer increased the surface hardness of substrate. Phase analysis by using XRD accompanied with chemical composition studies by EDS analysis revealed that the clad layer was comprised FeAl intermetallic as the matrix with Fe3Al and FeAl3 needle-like intermetallics distributed in the clad layer. Results of oxidation test of samples at 500°C for 10-100hr showed the Al-rich clad improves oxidation resistance of samples significantly. In addition، Al rich overlayer increases surface hardness of substrate to 270 Vickers which is twice of substrate hardness.