Nanoindentation measurements of the bulk specimens before and after ion beam irradiation was conducted using a G200 Nanoindenter system with a Berkovich-type indentation tip. The maximum load and indentation depth in this study was kept at 220 mN and 1400 nm, respectively. The experimental hardness and elastic modulus was determined by analyzing load–displacement (P–h) curves using the Oliver and Pharr method [17,18].