Corrosion Effects on High-cycle Fatigue Lifetime and Fracture Behavior for Heat-treated Aluminum-matrix Nano-clay-composite Compared to Piston Aluminum Alloy

In this research, the corrosion effect has been investigated on the high-cycle fatigue lifetime and the fracture behavior for the heat-treated aluminum-matrix nano-clay-composite and piston aluminum alloys. For this objective, after fabricating stir-casted nano-clay-composite, standard samples were machined and rotary bending fatigue tests were performed. To study the corrosion effect, some specimens were corroded in the 0.00235 % H2SO4 solution after 200 h and then, they were tested under cyclic bending loading. Due to increase in the hardness by adding nano-clay particles and the heat treatment, higher fatigue strength occurred, compared to the base material. Moreover, nano-clay particles shortened the fatigue lifetime; however, this effect was less in the corrosion-fatigue lifetime. In addition, the failure mechanism was the brittle fracture behavior due to the observation of quasi-cleavage and cleavage marks. Experimental data illustrated that the H2SO4 environment effect was effectively significant on the bending fatigue lifetime of the piston aluminum alloy, due to corrosion pits and surface defects. This degradation in material properties was demonstrated as a decreasing shift in both low-cycle and high-cycle fatigue regimes.