Tensile deformation and fracture behavior of spray-deposition 7075/15SiC p aluminum matrix composite sheet at elevated temperatures

Abstract

The tensile deformation and fracture behavior of spray-deposition 7075/15SiC p (15 vol.% SiC particle) aluminum matrix composite sheet were studied by uniaxial tension tests at temperatures ranging from 300 °C to 450 °C and strain rates of 0.001–0.1 s − 1 , and the fracture surfaces were examined by using a scanning electron microscopy. The results show that strain softening is present up to the point of failure and the flow stress level increases with increasing strain rate but decreases with increasing temperature. The total elongation to fracture increases with increasing temperature and with decreasing strain rate. The maximum strain rate sensitivity exponent is 0.24 which is much lower than that of typical superplastic materials. The apparent activation energy is calculated to be approximately 379 kJ/mol which is much higher than its unreinforced counterpart. The fracture surface morphology shows a large amount of localized plastic deformation in the aluminum matrix and numerous large cavities around the reinforcement. The absence of strain accommodation by interface sliding might have caused premature failure at the reinforcement/matrix interface.