Sharif Digital Repository

An architectural modification method was utilized to improve fracture toughness of discontinuously reinforced aluminum (DRA) composites. Al-DRA composites having a structure similar to that of reinforced concrete were fabricated. The number of reinforcing DRA rods within Al matrix and volume fraction of SiC particles in DRA were altered to evaluate their effect on fracture behavior of these materials. It was found that architectural modification does not have any destructive influence on elastic modulus and yield strength of the composite. Moreover, the success of this method on toughness improvement strongly depends on the occurrence of debonding between Al and DRA regions upon loading  

Lamination has been shown to enhance damage tolerance of discontinuously reinforced aluminum (DRA) composites. Doing this technique, DRA layers could be laminated with ductile interlayers. In this research, two types of laminates consisting similar DRA layers and a ductile AA1050 interlayer were fabricated by means of hot roll-bonding. AA6061-5. vol% SiCp and AA6061-15. vol% SiCp composites were considered as exterior layers. Different rolling strains, was applied to control the interfacial strength which was examined by shear test. Toughness behavior of laminates was evaluated by three-point bending test in crack-divider orientation. Based on obtained results, the plastic deformation of... 

The present research aims to investigate the development of brass reinforced aluminum composites during dissimilar friction stir welding of brass and aluminum. Moreover, to probe the effect of such a metal matrix composite on its bed, the cross-sectional properties of joint area are studied in two aspects of corrosion behavior and hardness distribution. Microstructural investigations through optical and electron microscopy show development of lamellar composites within the top site of the stir zone and aluminum surface. The measured iso-hardness contours indicate that evolved composite structures increase the cross-sectional hardness of aluminum locally. Also, the electrochemical assessment...