Development of in-situ hybrid phase reinforced Mg-based metallic glass matrix composites

Abstract

The in-situ NiTi(Nb)+β-Nb hybrid reinforcing structures have been successfully induced in a Mg-based amorphous matrix by using the novel selective phase leaching process. The size of secondary phase can be refined by increasing the cooling rate of the pre-alloys and the hybrid structure can be obtained by as-followed annealing treatment. The fracture strength of the composite improved to over 1 GPa and the plastic strain to over 13%. The ductile secondary phase is found to be effective in hindering the rapid propagation of main shear bands and contribute to the generation of multiple shear bands. The fine size of secondary phase is very close to the processing zone size of the matrix, which should further improve the interactions between the reinforcing phases and the matrix. The hybrid structure can induce a more complex stress field during deformation and may lead a breakthrough in designing the amorphous matrix composites.