Polycrystalline aluminum samples are irradiated with 40‐keV He+. At moderate target temperatures (∼0.3Tm) a prominent and distinct enhancement of the light intensity from sputtered excited aluminum atoms is observed after implantation to a critical dose of 4×1017He+/cm2. It is shown that this effect is associated with a sudden increase in the erosion rate of Al and in the surface exfoliation due to radiation blistering. At higher target temperatures (∼0.7Tm) a less pronounced increase in the photon intensity and a different surface structure is observed.