Tungsten Heavy Alloys with Two phase Matrix

Abstract

WNiCo alloys subjected to a two-stage or cyclic heat treatment develop a unique microstructure wherein apart from tungsten grains and matrix phase, fine tungsten precipitates are distributed in the matrix. This is unlike conventional heavy alloys such as WNiFe and WNiFeCo where the matrix is single phase without any secondary microstructural features. The purpose of developing a two-phase matrix is to realise superior mechanical properties compared to conventional alloys, especially strength with comparable or superior elongation and impact toughness. This advantage has rendered WNiCo alloys (with two-phase matrix) suitable candidates for advanced kinetic energy penetrators. The present study focusses on processing 92W-5Ni-3Co alloy using cyclic heat treatment and optimisation of parameters involved in cyclic heat treatment as well as subsequent vacuum heat treatment. Any refinement in processing parameters will help in improving the mechanical properties given the fact that processing parameters, microstructural features and mechanical properties are strongly interdependent in the case of tungsten heavy alloys.