Research on the novel Al–W alloy powder with high volumetric combustion enthalpy

Abstract

Abstract Al–xW alloy powder (x = 10, 20, 30, 40, 50 wt.%) was prepared by thermite reduction method and gas atomization method. The phase identification, surface morphology, spatial phase structure, oxidation behavior and combustion performance of the alloy powder were investigated by XRD, SEM/EDS, DSC, DTA/TG and oxygen bomb tests, respectively. The results show that among Al–xW alloy powder, Al–20W alloy powder has the largest volumetric combustion enthalpy measured in an oxygen bomb calorimeter (83,440 ± 790 J/cm3), which is superior to pure Al powder. Al–20W alloy powder has good sphericity and exhibits a special spatial phase structure, in which the metastable Al/W intermetallic compound is distributed in the pure Al matrix. In the process of stabilization, metastable phase transforms into the stable Al12W and release energy. The study of thermal oxidation behavior shows that Al–20W alloy powder has excellent thermal oxidation activity and oxidation completeness in air. Al–20W alloy powder is almost completely oxidized in air at 1500 °C, and only Al2O3 is detected in the oxidation product. The oxidation product particles of Al–20W alloy powder at 1500 °C are in the shape of a hollow shell. The combustion of Al–20W alloy powder produces a large amount of gaseous combustion product WO3, which is beneficial to increase the pressure inside the solid-propellant rocket engine. In summary, Al–W alloy powder has excellent application prospects in the field of energetic materials such as solid propellants and explosives.