Effect of intense pulsed ion beams irradiation on the oxidation behavior of γ′-based superalloy

Intense pulsed ion beams (IPIB) with three different power densities (25, 37.5 and 50 MW/cm2) are employed for the surface treatment of c0-based superalloy IC6. The influence of IPIBirradiation on the oxidation behavior of IC6 at 1100 C for up to 100 h is investigated. It is found that the phase states of IC6 are dramatically changed after IPIBirradiation and the oxidation behavior of the irradiated coupons depends greatly on the power density of IPIB. IPIB irradiation with a power density of 25 or 37.5 MW/cm2 significantly reduces the oxidation rate with respect to the unirradiated coupon. The improvement of the oxidation resistance can be attributed to a change in the oxidation products from a three-layered scale of Ni-rich oxides for the unirradiated coupon to a two-layered scale of Mo- and Al-rich oxides. In contrast, IPIBirradiation with a power density of 50 MW/cm2 proves to be detrimental, causing a higher oxidation rate. The oxidation mechanism for IPIBirradiated coupons is discussed.