Nanosecond pulsed laser irradiation induced hierarchical micro/nanostructures on Zr-based metallic glass substrate

Abstract

A large effective surface area is beneficial to enhance the applications of metallic glasses (MGs) in heterogeneous catalysis and biomedical engineering. For the purpose of increasing effective surface area, in this study, hierarchical micro/nanostructures were fabricated on a Zr-based MG substrate by nanosecond pulsed laser irradiation. Experimental results indicated that a layer of micron-scale laser pulse tracks covered by a cotton-like MG thin film with nanometer-scale microstructure was formed in the laser irradiated region. This hierarchical micro/nanostructures retained amorphous characteristic and exhibited uniform element distribution. Its formation mechanism was investigated by analyzing the laser irradiation process and morphologies. Nanoindentation results indicated that the cotton-like MG thin film was very loose and soft compared to the as-cast MG substrate, showing different plastic deformation behavior. Results from this study indicate that nanosecond pulsed laser irradiation is an effective method to generate hierarchical micro/nanostructures on MG substrates, which can increase their effective surface areas and improve their potential applications as biomaterials and catalysts.