The structural relaxation effect on the nanomechanical properties of a Ti-based bulk metallic glass

•The effect of structural relaxation on the nano-mechanical behaviors of BMGs is studied.•The indent load at first pop-in event, the hardness and Young’s modulus are enhanced after annealing.•The differences in nanomechanical properties can be attributed to their different atomic structure. Indentation experiments were performed on the as-cast and the annealed Ti-based bulk metallic glass samples to investigate the effect of structural relaxation on the nanomechanical behaviors of the material. The onset of pop-in event, Young’s modulus, and hardness were found to be sensitive to the structural relaxation of the testing material. The difference in nanomechanical properties between the as-cast and annealed BMG samples is interpreted in terms of free volume theory.