Effects of surface shape on thermal fatigue resistance of biomimetic non-smooth cast iron

According to the principle of bionics, the experimental samples with a biomimetic non-smooth surface were manufactured using a laser. Three kinds of shapes including ‘spot’, ‘striation’ and ‘lattice’, were chosen for forming the non-smooth surface. With the self-controlled thermal fatigue test method, the thermal fatigue behavior of smooth and non-smooth samples was investigated and compared. The results indicated that the biomimetic non-smooth surface had a beneficial effect on improving the thermal fatigue behavior of gray cast iron, and that the non-smooth sample with the lattice shape had the highest resistance to thermal fatigue. Compared to the base material, the non-smooth unit zone was characterized by the alteration of microstructure. The lack of the graphite phase, the enhancing of mechanical properties in the unit zone and the effects of thermal crack deflection are the main reasons for improving the thermal fatigue resistance of gray cast iron with the biomimetic non-smooth surface.