Effects of Y on helium behavior in Y-doped TiH2 films prepared by magnetron sputtering

TiH2 and yttrium-doped TiH2 alloy films with different helium concentrations prepared by magnetron sputtering were investigated using ion beam analysis (IBA), X-ray diffraction (XRD), thermal helium desorption spectrometry (THDS), positron annihilation spectroscopy (PAS) and nanoindentation techniques. It was found that through increasing the concentration of doped Y atoms, strong release peaks of helium will be found at about 820 K. The release at 820 K corresponds to the binding energy of the helium state on grain boundary indicating that the majority of the helium exists in the grain boundaries. In addition, the results of XRD and nanoindentation indicate that the doping of Y in the TiH2 films can improve the hardness and the elastic modulus of the films because of the fine-grain strengthening caused by the decreased size of TiH2 grains.