Strain and structure order variation of pure aluminum due to helium irradiation

Abstract

Damage induced by helium ion irradiation in 1060 pure aluminum was investigated with a home-made MT3-R ion implanter. In this process, 10¹⁵, 10¹⁶ and 10¹⁷ ions per cm² irradiation were used with a voltage of 50 kV. In order to evaluate the irradiation damage in samples, surface morphology changes, strain variation and microstructure transformation have been examined using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Besides, detailed collision events of energetic ions with target atoms were simulated using SRIM-2008. The result shows that the irradiation dose plays the most important role in changing the target surface layer. Increasing the irradiation dose further damaged the surface layer morphology and increased surface roughness. In this process, strain changes and phase transformation caused by the ordered crystal structure being broken were discussed and a mechanism was proposed to explain the phenomenon that appeared at different irradiation stages. In addition, the variation of dislocations observed by TEM confirmed this conclusion.