Effect of Si on the mechanical and tribological properties of FeCoNiBSiNb amorphous alloy composites prepared by laser melting

Abstract [(Fe 0.6 Co 0.2 Ni 0.2 ) 0.75-0.03x B 0.2 Si 0.05+0.03x ] 96 Nb 4 amorphous/crystalline composite layers were fabricated using laser cladding by adjusting the contents of Si (x= 0, 1, 2, 3, 4, 5, 6). The microstructure and tribological performance of the layers were studied. Additionally, the effect of Si on the glass forming ability (GFA) of the layers was understood. Results show that an appropriate Si content can refine the microstructure of the FeCoNiBSiNb laser cladding layers and improve the mechanical and tribological properties. The hardness of the cladding layers increases monotonically with increasing Si contents,when Si (x=0) the corresponding layer has the smallest microhardness (734.2HV 0.1 ) and Si (x=3) the corresponding layer has the largest microhardness (1106HV 0.1 ),whereas the amorphous content and compressive strength increase first and then decrease. When x=2, the fracture strength of the layer reaches the biggest (2880 MPa). When x>2, the fracture strength of the cladding layer decreases as x value increases.On the contrary, the wear volume loss decreases first and then increases as Si contents increase. When the Si content is 10.56 at.% (x=2), the cladding layer exhibits the highest amorphous content (42 %), the biggest compressive strength (2880 MPa), and the best dry friction performance.