Effect of Ni on the Properties of a Laser Surface-Clad Fe-Based Alloy

Abstract

Two Fe-based alloys , Fe-15Cr-5Ni and Fe-16Cr-7Ni (wt. %), with a small variation in the Ni content were fabricated on a martensitic stainless steel 1Cr13 substrate by laser surface cladding (LSC) using a CO2 laser and Ar shielding gas that was blown into a moten pool. Both LSC alloys exhibited typical rapid directional solidification structures. However, 2 wt% Ni increase led to ~9% increase in the weight fraction of austenite, and ~5% increase in the area proportion of interdendritic regions which contained the higher Cr contents. These microstructural changes caused a great reduction in the microhardness and great improvements in the resistance to electrochemical corrosion in 0.5M H2SO4 solution. The reasons for these differences are discussed in detail.