Tensile and Fatigue Behavior in Clay Reinforced Nylon 6 Nanocomposites
Shijie ZHU, Masanori OKAZAKI, Arimitsu USUKI and Makoto KATO
Abstract:It is shown that 2 wt% clay-reinforced nylon and 4 wt% clay-reinforced nylon have similar tensile strengths, which are increased by about 30% compared to those of nylon 6. With an increase in loading rate, the ultimate tensile strength increases for both nylon 6 and nanocomposites, and the ductility decreases for nylon 6 while it does not change obviously or even increase a little for nanocomposites. The fatigue strength of 2 wt% clay-reinforced nylon is also increased by about 30% compared to that of nylon 6, but the fatigue strength of 4 wt% clay-reinforced nylon is slightly increased or similar to that of nylon 6. The cyclic deformation has been examined using stress-strain hysteresis loops. The small cyclic deformation in 4 wt% clay-reinforced nylon is attributed to the no increase in fatigue strength. The strain incompatibility near the phase boundary leads to the relaxation of three dimensional stress field in 2 wt% nano-composite, while leads to the extraction of clay platelets in 4 wt% nano-composite. Furthermore, time-dependent behavior and microscopic damage mechanisms are discussed. Key Words:Nanocomposite, Cyclic deformation, Fatigue, Time-dependent behavior, Crack, Fracture surface