Experimental investigation of plane stress fracture toughness for Al/Cu/Al multilayer produced by Cold Roll Bonding method

In recent years, metallic multilayer material have been attention of many researchers and different industries. Cold roll bonding is one of the method for produce layered composite that compared to other composite manufacturing methods are more economically and have the ability to produce layered composite with different material. In this research, for the first time and according to ASTM-E561 and using compact tension specimens investigated plane stress fracture toughness for thin three-layer Al/Cu/Al composite sheets produced by Cold Roll Bonding Process. The fracture toughness is an important parameter in the design that their analysis can predict crack growth and life for material has crack. In addition to the fracture toughness, mechanical properties and tensile fracture surfaces were evaluated by using of uni-axial tensile test, micro hardness and scanning electron and optic microscopy, respectively. Results of carried out tests, showed the value of tensile strength, microhardness and fracture toughness for Al/Cu/Al layered composite compared to initial Al 5052 and pure Cu, increased that the main cause of this increase is applied high strain and cold working. Value of fracture toughness for Al/Cu/Al layered composite received 38.7MPa.m1/2 that compared to initial Al5052 and pure Cu, 81% and 165% enhanced, respectively. Results of SEM demonstrated that ductile fracture mechanism govern for Al/Cu/Al composite such as initial samples, but the difference is that dimples for composite layers shallower and smaller compared to initial samples.