Research On The Effect Of Tungsten On The Structure And Properties Of Energetic Alloy Materials

Energetic alloy materials can be used as metal fuels and energetic structural materials in explosives and warheads,respectively.The most widely used metal fuel in explosives is pure Al powder,but it has the disadvantage of incomplete oxidation and combustion;The existing energetic structural materials used in warheads generally have the problem of not being able to take into account density,strength,and plasticity.Tungsten（W）with high density has potential application value in the field of metal fuels and energetic structural materials.The purpose of this study is to reveal the impact of W on the structure and performance of energetic alloy materials,provide guidance for the development of the next generation of high-density,high-performance Al-based alloy fuels and Zr-based Bulk Metallic Glass（BMG）energetic structural materials,and meet the demand for new energetic alloy materials for explosives and warheads.A series of Al-W energetic alloy powders were prepared by combining the aluminothermic reduction method with the high-temperature gas atomization method,and their phase structure,oxidation performance,and combustion performance were deeply studied.It is found that Al-20W,Al-25W,and Al-30W energetic alloy powders exhibit the phase structure in which metastable（including amorphous）Al/W alloy phases are uniformly distributed on the pure Al matrix.As temperature increases,the types and morphologies of Al/W alloy phases change.Al-W energetic alloy powder has better thermal oxidation activity and oxidation completeness than pure Al powder.With the increase of W content,the temperature required for complete oxidation of Al-W energetic alloy powder gradually decreases.Al-30W energetic alloy powder can be completely oxidized in air at 1300℃,and only fragments of Al₂O₃ remain in the oxidation product.Compared to pure Al powder,the density and measured volumetric combustion enthalpy of Al-W energetic alloy powder are higher.As the W content increases,the measured density gradually increases,and the measured volumetric combustion enthalpy slightly decreases.The volumetric combustion enthalpy of Al-20W energetic alloy powder is the highest,reaching（83440±786）J/cm³,exceeding the theoretical volumetric combustion enthalpy of pure Al powder.During oxidation or combustion,all W atoms in Al-W energetic alloy powder ultimately transform into gaseous product WO₃.The significant improvement of the oxidation performance of Al-W energetic alloys by W is mainly reflected in the fact that the oxidation product WO₃ of the Al/W alloy phase not only promotes the oxidation of the pure Al phase but also volatilizes itself in gaseous form.The novel Zr-based BMG-W energetic structural materials with high density,high strength,good plasticity,and excellent damage performance were prepared by spark plasma sintering,and their microstructure,mechanical properties,combustion performance,and damage performance were systematically studied.Zr-based BMG-W energetic structural materials with a sintering temperature of 365℃or above and a W content of 20 vol.%to 50 vol.%have similar fracture strength（not less than 1600 MPa）and better plastic deformation ability（plastic strain greater than 5%）to Vit-1 BMG(Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5)prepared under the same conditions.The mechanism by which W enhances the plasticity of Zr based BMG energetic alloys includes W particles hindering the extension of shear bands and promoting their rotation,proliferation,and plastic deformation under stress.The fracture strength and failure strain of Zr-based BMG-W energetic structural materials under dynamic compression at the same strain rate are both greater than Vit-1 BMG,and the higher the W content,the higher the fracture strength and the failure strain tend to increase.The higher the strain rate,the lower the W content,the shorter the ignition delay time,the faster the flame propagation speed,and the longer the combustion duration of Zr-based BMG-W energetic structural materials during dynamic compression.Vit-1 BMG cannot effectively damage the aftereffect aluminum target,and Zr-based BMG-W energetic structural materials have better damage performance.The damage effect on aluminum targets shows a trend of first increasing and then decreasing with the increase of W content.BMG-40W energetic structural materials have the largest perforation area and expansion ratio on aluminum targets,with 5658.6mm² and 55.24,respectively.