Composition and structure of Al ions implanted Fe at elevated temperatures

Al ions with ion energy of 120 keV are implanted into Fe under ion current density of 3.18 μA/cm2 to implantation doses of 5 × 1016 and 1 × 1017 ions/cm2 at room temperature and elevated temperatures of 250 and 500 °C, respectively. At 250 °C, the distribution depth of implanted Al reaches 160 nm with a peak concentration of 6 at.% at the dose of 5 × 1016 ions/cm2, and 180 nm with 10 at.% at 1 × 1017 ions/cm2, analyzed by Rutherford backscattering spectroscopy, respectively. At 500 °C, the implantation depth is 200 nm and the maximum concentration of Al is 10 at.% at the dose of 1 × 1017 ions/cm2. With 5 × 1016 ions/cm2, the intermetallics Al13Fe4 is formed in the Fe samples at 500 °C, revealed by X-ray diffraction. With 1 × 1017 ions/cm2, the phase is also detected at 250 °C. The concentration-depth profiles of implanted Al in Fe samples at the room temperature, 250 °C and 500 °C are calculated by a mass transfer model that is built based on the transport of ions in matter and the irradiation enhanced diffusion. The calculated concentration-depth profiles are in reasonable agreement with those obtained from the experiments.