Fabrication of Al/BN composite strips and evaluation of fracture toughness and forming limit diagram

Abstract

In this study, mechanical properties, fracture toughness (FT) and forming limit diagram (FLD) of Al base composites manufactured by accumulative roll bonding (ARB) have been studies experimentally. AA1100/BN composite strips have been manufactured with thickness of 1 mm up to 10 ARB cycles at 300°C. Their strength enhanced to 168 MPa which was 248 % enhancement than the primary aluminum alloy 1100. Also, the bonding between layers enhanced by fabrication of thin layers through the thickness of composites with more plastic strains. SEM fracture morphology of composites showed that a shear ductile fracture was achieved at higher passes. So, relative to the annealed sample, deep dimples are shrinking slowly. UTS, elongation and hardness of samples improved to 169 MPa, 11.4 % and 55.6 HV after the 10 cycle, respectively. After the first pass as the criterion of formability, the area under the FLDs dropped sharply and then enhanced at higher passes. Based on the results obtained FT enhanced to 30 MPam12 at the 10th pass.