Multiscale Analysis of Adiabatic Shear Bands in Tungsten Heavy Alloy Particulate Composites

Abstract

We use a multiscale approach to analyze adiabatic shear bands in a tungsten heavy alloy particulate composite deformed in plane strain tension at a nominal strain rate of 5000/s. Fifty μm diameter circular tungsten particulates are assumed to be randomly distributed and perfectly bonded to the nickel-iron matrix. The volume fraction of particulates equals 50%. We first analyze transient coupled thermo-mechanical deformations of a homogenized body with values of thermophysical material parameters equivalent to those of the particulate composite. Time histories of deformation variables on the bounding surfaces of the centrally located 2 mm × 2 mm subregion of the 10 mm × 10 mm region are recorded. Boundary conditions of surface tractions and temperature rather than of velocities and temperature are then used to analyze plane strain coupled thermomechanical deformations of the 2 mm × 2 mm composite in which tungsten particulates are randomly distributed in the central 1 mm × 1 mm subregion of the 2 mm × 2 mm region with the remaining part comprised of the equivalent homogeneous material of the 10 mm × 10 mm body. It is found that the multiscale analysis of the problem gives an adiabatic shear band initiation time of ∼ 22 μs as compared to ∼ 58 μs in the equivalent homogenized body and ∼ 50 μs in the macroanalysis of deformations of the 1 mm × 1 mm region containing a randomly distributed 50% volume fraction of 50 μm diameter tungsten particulates.