CERAMICS INTERNATIONAL Available online at www.sciencedirect.com Ceramics International 40 (2014) 10027–10035 Hybrid composites produced by anodizing and accumulative roll bonding (ARB) processes Mohammad Reza Toroghinejad a , Roohollah Jamaati b,n , Ali Nooryan a , Hossein Edris a a Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran b Young Researchers and Elite Club, Ayatollah Amoli Branch, Islamic Azad University, Amol, Iran Received 17 February 2014; received in revised form 23 February 2014; accepted 24 February 2014 Available online 6 March 2014 Abstract In this study, microstructure and mechanical properties of Al/1.6 vol% Al 2 O 3 /1.5 vol% B 4 C hybrid composite produced by anodizing and accumulative roll bonding (ARB) processes were investigated. Microstructural observations and fractography were performed by scanning electron microscopy (SEM). Also, the mechanical properties were investigated by tensile and microhardness tests. It was found that with increasing the number of ARB cycles, a better distribution of Al 2 O 3 and B 4 C particles was obtained in the aluminum matrix. The hybrid composite after the tenth cycle demonstrated a uniform distribution and a strong bonding between the particles and the matrix without any porosity. Furthermore, ARB-processed monolithic and also, the hybrid composite showed much higher tensile strength than the annealed aluminum sample. In addition, elongation of ARB-processed monolithic and also, the hybrid composite was decreased in the first step and then increased as a result of increasing the number of cycles. Moreover, the ARB-processed monolithic and the hybrid composite exhibited higher hardness than the annealed aluminum. Finally, it was realized that the monolithic and hybrid composite samples had a shear ductile fracture, dimples and shear zones. However, the number of sources in the void nucleation of the composite was more than that of the monolithic sample. & 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved. Keywords: C. Mechanical properties; Hybrid composite; Anodizing; Accumulative roll bonding; Microstructure 1. Introduction Metal matrix composites (MMCs) represent a new genera- tion of engineering materials due to their special mechanical and physical properties. A strong ceramic reinforcement is incorporated into a metal matrix to improve its properties including specific strength, specific stiffness, wear resistance, excellent corrosion resistance and high elastic modulus [1–6]. MMCs combine metallic properties of matrix alloys (ductility and toughness) with ceramic properties of reinforcements (high strength and high modulus), leading to greater strength in shear and compression and higher service–temperature capabilities. Therefore, MMCs tend to replace conventional materials in various fields of application such as automotive, aeronautical, aerospace, and mechanical engineering, as well as other industries because of their intrinsic properties [1,2,4,6]. MMCs have been made mainly by casting and powder metallurgy techniques [7–14]. These methods involve the use of high temperature and result in the softening of the metallic reinforcement and the interactions in the interface of matrix and reinforcement. As a result, the mechanical properties of the composites may be reduced. Recently, accumulative roll bonding (ARB) process has been used as a new effective method to fabricate the MMCs [15–23]. Combining the three strengthening mechanisms, including strain hardening, grain refinement, and second phase particles in the ARB-processed MMC, leads to the production of high-strength composites. Recently, some efforts have been directed toward fabricating ARB-processed hybrid composite reinforced by the two types of particles simultaneously [24–26]. In these researches, the effect of the number of ARB cycles and particle content on the micro- structure and mechanical properties has been investigated. www.elsevier.com/locate/ceramint http://dx.doi.org/10.1016/j.ceramint.2014.02.102 0272-8842 & 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved. n Corresponding author. Tel.: þ98 911 2124023. E-mail addresses: r.jamaatikenari@ma.iut.ac.ir, roohollah144@gmail.com (R. Jamaati).