Experimental investigation on the mechanical and tribological coupled behaviour of bimetal composite under different states

Wear resistance and excellent mechanical properties are the main requirements in industrial applications of bimetal composites. The interfacial evolution of duplex stainless steel/low carbon steel (2205/AH36) bimetal composite after annealing and its tribological behaviour in a 3.5 wt% NaCl solution were investigated in this study. The bonding interface evolution between two layers plays a critical role in mechanical properties of composite, and the surface microstructure of stainless steel layer determines the wear and corrosion resistance. The hot-rolled composite samples were heat treated at temperatures ranging from 850 to 1150 °C in steps of 100 °C for 1 h. Optical microscopy (OM) and electron backscattered diffraction (EBSD) were employed to investigate the microstructural evolution of both component layers and bonding interface. The uniaxial tensile tests were used to investigate the tensile strength and elongation of composites after annealing at different temperatures. Ball-on-disc sliding tests were employed to study the tribological behaviour of bimetal composite, with sample discs being immersed in the solution. The variations of the coefficient of friction (COF) were recorded as a function of the sliding time, and the wear tracks of discs after tribological tests were observed by the laser scanning microscope and a scanning electron microscope (SEM). The results show that the annealing temperature significantly affects the width of bonding interface, and the total wear volume loss of duplex stainless steel of composite is dominated by the mechanical wear in the chloride solution.