Impact response of a tungsten heavy alloy over 23–1100 °C temperature range

Abstract

Impact response of a tungsten heavy alloy (WHA) prepared by liquid phase sintering of tungsten powder (∼80 vol. %) with an Ni–Co–Fe (3.50–1.25–1.0 weight ratio) binder was studied over a 23–1100 °C temperature range in a series of planar impact tests accompanied by continuous monitoring of the velocity of the WHA sample rear surface. The temperature dependence of the proof stress Y0.1(T) was found based on the 1D numerical simulations of the performed impact tests using a modified Steinberg–Cohran–Guinan constitutive model, and the temperature dependencies of the density ρ0(T) and longitudinal cl(T) and bulk cb(T) speeds of sound were found using rule of mixtures. The bulk speed of sound cb(T) was also used in determination of the temperature dependence of the spall strength σsp(T) of the alloy based on the experimentally recorded velocity pull-backs Δupb. The strong decrease of both Y0.1(T) and σsp(T) with temperature (Y0.1 decreases almost sixfold between 23 and 1100 °C) allows one to assume that the tensile (spall) fracture of the alloy is controlled by the strength of its matrix.