Annealing effects on the structure and hardness of helium‐irradiated Cr ₂ AlC thin films

Abstract

Abstract Cr 2 AlC MAX phase thin films prepared by radio‐frequency magnetron sputtering were irradiated at room temperature by 100 keV helium ions to a fluence of 1 × 10 17 ions cm −2 . The effects of thermal annealing on the structural and mechanical properties of the helium‐irradiated Cr 2 AlC films as well as the helium release were investigated by grazing‐incidence X‐ray diffraction (GIXRD), Raman spectroscopy, and scanning electron microscope (SEM) in combination with nano‐indentation and elastic recoil detection (ERD) analysis. The irradiation‐induced structural damage in the Cr 2 AlC is significantly recovered by thermal annealing at temperatures around 600℃, attributed to high defect diffusivity. After annealing to 750℃, the hardness of irradiated films recovered almost completely, which is ascribes to both defect recombination and reformation of damaged chemical bonds. Substantial helium release occurring at this annealing temperature is closely related to the damage recovery due to helium irradiation.