Study on Microstructure and Properties of FV520B Stainless Steel Brazed Joints with (CuCrNiMn)100−xSix Multi-component Filler Metal

Abstract

High-entropy alloys (HEAs) exhibit exceptional properties derived from unique phase structures and chemical composition design. Appropriately designed HEAs show great potential as filler materials for joining fan impellers and blades. In this study, multi-component filler metals based on the (CuCrNiMn)_100−xSi_x system were employed to braze FV520B stainless steel joints. Following vacuum brazing, the joints fabricated with filler metals containing varying Si contents were analyzed in terms of microstructure, phase composition, diffusion kinetics, and mechanical properties. The results indicate that increasing the Si content significantly mitigates intergranular cracking in the brazed joints, and the microstructure primarily consists of an FCC-structured Cr_0.19Fe_0.7Ni_0.11 solid solution and a Cu-Ni solid solution. The Si element with a small atomic radius needs less critical energy through the grain boundary, which drives other metal elements to have strong diffusion behavior. As the Si content increases, the diffusion coefficients of each element increase, and the diffusion distances extend, which subsequently influences the chemical composition and mechanical properties of the brazed seam. The best filler metal composition is (CuCrNiMn)₉₅Si₅, and the shear strength is 256 MPa.