Laser shock compression induced crystallization of Ce3Al metallic glass

Abstract

Laser shock compression studies on Ce3Al metallic glass performed using a 3 J Nd:YAG laser indicate shock-induced crystallization, evidenced by the presence of a two-wave/stepped particle velocity profile and structural changes observed via X-ray Diffraction (XRD) analysis of recovered material. A direct shock-compression setup was designed with 25 μm thick Ni driver foil, 40 μm thick Ce3Al metallic glass ribbon, and 3 mm thick poly(methyl methacrylate) (PMMA) backer window for use with input laser energies varying from 100 to 2000 mJ and corresponding estimated peak pressures of 1.4 to 4.1 GPa in Ce3Al. At shock pressures below ∼1.8 GPa (300 mJ laser input energy), samples were recovered showing no obvious deformation or structural changes evidenced via XRD analysis. At higher laser energies and shock pressures above the elastic limit, samples were recovered showing visible deformation and crystallization evidenced by Rietveld analysis of diffraction patterns. The corresponding velocity profiles also showed a stepped wave structure, increasing in magnitude with energy. The overall results reveal possible densification of the glass due to delocalization of 4f electrons in Ce at lower laser shock pressures and increased crystallization with preferred orientation and distortion of the nanocrystals at higher shock compression conditions.