Elucidating the role of processing parameters on microstructure,grain refinement,and mechanical features of Al/Ti laminated composite fabricated by accumulative roll bonding

Abstract

Multilayered composites are widely used in automobile components. The properties of multilayered composites mainly depend on processing parameters. In this investigation, Al/Ti composites were fabricated by accumulative roll bonding (ARB). The influence of rolling parameters including rolling velocity (10 < v < 20 r/min), rolling cycle (7 cycles), and friction coefficient (0.08 < µ < 0.14) on the evolution of microstructure, grain refinement, variations of hardness, and tensile features were examined. The results of microstructural characterization showed that the layers became more discontinuous and the broken pieces of Ti were better distributed in the Al matrix when the rolling cycle and rolling friction increased and the rolling velocity decreased. In addition, the characterization of grain structure revealed grain refinement in Ti and Al layers after the 7^th cycle. The grain structure was better refined when the friction coefficient was 0.14 and rolling velocity was 10 r/min. The hardness and strength values increased as the rolling cycle and friction coefficient increased and the rolling velocity decreased. When the friction coefficient was 0.14 and the rolling velocity was 20 r/min, the highest strength of 520 MPa was obtained and the maximum hardness of Ti and Al were 76 HV and 292 HV, respectively. Although the fracture surfaces showed delamination and different sizes of dimples, a larger number of dimples were observed at higher rolling velocities and lower friction coefficients.