Effect of accumulative roll bonding cycles on the dry wear behavior of St14/Cu10Zn multilayered composites under different load conditions

This study investigates the fabrication of St14/Cu10Zn multilayered composites using accumulative roll bonding (ARB) process. The composites were processed through 2, 4, and 6 ARB cycles and evaluated under pin-on-disk wear tests at applied loads of 10, 15, 20, and 25 N. Microstructural observations revealed progressive layer refinement and thickness reduction with increasing ARB cycles. At the sixth cycle, severe plastic deformation induced necking and shear band formation in the steel layers, leading to their fragmentation and uniform dispersion within the brass matrix. Mechanical results showed a continuous increase in strength from 305 MPa (St14) and 297 MPa (brass) in the initial state to 615 MPa after 2 cycles and 727 MPa after 6 cycles, while ductility slightly decreased from 8.5% to 7.6%. Hardness reached 247 HV (steel) and 236 HV (brass) at the sixth cycle. Wear behavior strongly depended on ARB cycles and applied load. At 10 N, the sixth-cycle sample exhibited the lowest wear depth due to higher hardness and refined fragmented structure. At 25 N, wear depths were 60 μm (2 cycles), 40 μm (4 cycles), and 100 μm (6 cycles). The four-cycle composite showed superior wear resistance under higher loads due to stable oxide layer formation and controlled delamination, whereas the sixthcycle sample exhibited reduced performance because of fragmented steel islands and loss of loadbearing continuity. Wear mechanisms evolved from ploughing, plastic deformation, and cracking in low-cycle conditions to delamination and oxide-assisted wear in higher-cycle states.