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

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 Y 0.1 ( 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 ρ 0 ( T ) and longitudinal c l ( T ) and bulk c b ( T ) speeds of sound were found using rule of mixtures. The bulk speed of sound c b ( T ) was also used in determination of the temperature dependence of the spall strength σ s p ( T ) of the alloy based on the experimentally recorded velocity pull-backs Δ u p b. The strong decrease of both Y 0.1 ( T ) and σ s p ( T ) with temperature ( Y 0.1 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.