Effect of SiC particle size and severe deformation on mechanical properties and thermal conductivity of Cu/Al/Ni/SiC composite fabricated by ARB process

Abstract

SiC particles are among the most investigated types of reinforcing particles with high thermal conductivity in multilayered composites. This paper deals with the effect of the particle size and ARB rolled passes on tensile strength, elongation, and thermal conductivity of Cu/Al/Ni/SiC composite. Based upon the mechanical properties, the ultimate strength and the elongation of Cu/Al/Ni/SiC(2 μm) were more than that of Cu/Al/Ni/SiC(15 μm) at all passes, apart from the zero pass. This is because 2-μm particles not only tend to make smaller clusters than 15-μm particles but also are preferably trapped at the interfaces; however, 15-μm particles tend to be trapped in Al layers. Further, at each rolled pass, the values of thermal conductivity of Cu/Al/Ni/SiC (15 μm) were slightly higher compared to the other two composites. This is because of the larger cluster of 15-μm particles in the Al layers, providing better heat flux across the composite. In addition, the results of optical microscopy (OM) showed that applying more passes caused the discontinuity in all layers and also the non-uniform distribution of Ni and Al layers in the Cu matrix. Plus, due to the lower strength of Al layers in comparison to Cu and Ni layers, ceramic particles diffuse considerably in Al layers. The SEM images of the fracture surfaces indicated the ductile fracture with some uniaxial dimples for Al and Cu layers whereas for Ni layers both ductile and brittle cleavage fractures due to its higher work hardening exponent. • The fabrication of Cu/Al/Ni, Cu/Al/Ni/SiC(2 μm) and Cu/Al/Ni/SiC(15 μm) laminated composites was studied. • Effects of strain accumulation on all layers and the role of two sizes of SiC particles during four rolling passes of ARB process was investigated. • With increasing the strain accumulation, the ultimate strength of all three composites fluctuated due to the plastic instability of layers and the distribution of particles. • Reinforcing particles appeared in cluster shape at the interface of Al/Ni and Cu/Al because of being displaced by applied stress due to their small size and freedom of movement. Also, 15-μm particles were more trapped in Al layers than 2-μm trapped. • With increasing the strain accumulation, the elongations of composites decreased. • By increasing the number of ARB passes, thermal conductivity of composites dropped though at each pass Cu/Al/Ni/SiC(15 μm) had the highest values because of forming clusters at the interfaces.