Effect of cyclic heat treatment on the microstructure and mechanical properties of W-Ni-Co alloys

Abstract

Current generation heavy alloys with enhanced static as well as high strain rate properties are based on W-Ni-Co alloys. These alloys are subjected to a cyclic heat treatment to obtain fine tungsten precipitates in the matrix and to realise superior mechanical properties. The present study is focused on processing 92W-5Ni-3Co alloy using a post-sintering cyclic heat treatment to obtain fine tungsten precipitates in the matrix. As-sintered alloys and cyclic heat treated (in vacuum) alloys are then subjected to (i) vacuum heat treatment with oil quenching and (ii) nitrogen heat treatment with water quenching. A comparison has been drawn based on microstructural features and mechanical properties, between the alloys processed (i) with and without cyclic heat treatment and (ii) with oil and water quenching. This study thus helps in understanding the effect of cyclic heat treatment and quenching medium on the microstructure and mechanical properties of W-Ni-Co alloys.