LAUSR

Laser cladding of Fe-20Cr-10Ni-2Si alloy usually faces challenge of metallurgical defects like micropores and interdendritic fragile precipitates. In this paper, the laser cladding combined with friction stir processing (FSP) was applied to deal with this problem and prepare the nanostructured Fe-20Cr-10Ni-2Si alloy layer. The coarse dendritic grains (5 ~ 10 μm) of laser processed Fe-20Cr-10Ni-2Si alloy were broken into nanocrystallines which contain uniformly distributed nanoparticles (5 ~ 400 nm) in the deformation zone by FSP. The gradient microstructure with an average grain size of several nanometers on the top surface to several micrometers in the center part was obtained by FSP. Meanwhile, the grain size in the plastic zone decreases as the rotary speed rises. Grain refinement by FSP results in the increase of microhardness from 323 HV up to 583 HV, decreasing the friction coefficient from 0.42 to 0.35 and thus the wear resistance is improved.