Behavior of foreign-object-damaged WC/C-coated 7075-T6 aluminum alloy under fatigue loading

Solution heat treated and aged, 7075 is one of the most employed aluminum alloys because of its high mechanical resistance. A PVD WC/C coating is usually required to improve the wear resistance, but little information is available about its influence on fatigue life. Rotating bending fatigue tests were, hence, planned on smooth and coated samples. In many applications the components can be damaged by foreign objects. For this reason, some specimens belonging to both coated and uncoated series were damaged by an hardened steel sphere launched at high speed against the minimum cross section of the fatigue samples. The obtained samples series were, hence, tested for 104, 105, and 106 cycles. Finally, to study the effect of the coating from the static and the corrosion points of view, tensile and intergranular corrosion tests were performed, too.