Characterization, shear strength and corrosion resistance of self joining AISI 304 using a Ni Fe–Cr–Si metallic glass foil

Abstract

This work studied the microstructure of the interlayer formed after self joining of AISI 304 stainless steel, using a commercial metallic glass foil as the joining element and its effect on the shear and corrosion resistances at the interface zone. Different joining times and temperatures were used varying from 25 to 90min, and 800°C, 900°C and 1000°C, respectively. The joining process induced an inter-diffusion of alloy elements from the steel to the amorphous foil, conveying to the formation of intermetallics and second phases at the joining interphase, as was observed by SEM. The residual porosity at the joining zone was reduced as both, the bonding time and temperature increased. The mechanical behavior of the bonded samples was evaluated by shear tests presenting a maximum value of 108MPa for joints produced at 900°C for 60min, however the shear test presented values higher that 75MPa for the temperature vary from 850°C to 1000°C and time of 45min. Fractures occurred on the interlayer, indicating a strong relationship between the microstructure of the interface and the mechanical strength of the joints. Electrochemical tests in 3.5wt.% NaCl solution presented pitting corrosion at room temperature under conditions of open circuit potential in the form of preferential dissolution.