The effects of tungsten content on the mechanical behavior, ignition and energy-release characteristics of short-tungsten-fibers/Zr-BMGCs under dynamic loading

Abstract

The short tungsten fibers/Zr-based bulk metallic glass composites (SWF/Zr-BMGCs) were prepared by melt infiltration casting. The effects of tungsten content on mechanical properties and energy-release characteristics under dynamic loading of Zr_59.62Cu_14.4Ni₁₂Al₁₀Nb₃Hf_0.78Y_0.2 bulk metallic glasses (Zr-BMGs) were systematically investigated. Increasing tungsten content enhanced the mechanical strength of SWF/Zr-BMGCs from 1543 MPa to 1984 MPa by inhibiting propagation of shear bands, and ballistic gun tests demonstrated that tungsten fibers significantly improved the penetration capability of SWF/BMGC fragments. However, analysis of binarized images and quasi-closed chamber overpressure data indicated that the flare area and peak overpressure are reduced at the same impact velocity of 1000 m/s, reflecting a lower energy density per unit mass and reaction efficiency of 435.5 J/g and 4.14 % for SWF/Zr-BMGCs compared to 1592.1 J/g and 15.12 % of Zr-BMGs. This primarily results from the reduced exposed oxidation area during impact due to larger fragmented sizes and interfacial adhesion effects. In addition, the active elements Zr, Al, and Ni could burn preferentially under impact, which in turn contributes to the oxidation of elements Cu and W with high melting points. This work could improve the understanding of energy-release behavior of ex-situ second-phase reinforced Zr-BMGs under impact and support their further application.