Annealing effects on the structure and hardness of helium-irradiated Cr2AlC thin films

Cr2AlC 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 x 10(17)ions cm(-2). The effects of thermal annealing on the structural and mechanical properties of the helium-irradiated Cr2AlC 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 Cr2AlC is significantly recovered by thermal annealing at temperatures around 600celcius, attributed to high defect diffusivity. After annealing to 750celcius, 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.

Automated summary

Thermal annealing around 600 degrees Celsius significantly recovers structural damage in Cr2AlC caused by irradiation. After annealing to 750 degrees Celsius, the hardness of irradiated films almost completely recovers, mainly due to defect recombination and reformation of damaged chemical bonds. Substantial helium release at this annealing temperature is closely related to damage recovery from helium irradiation.