Effect of warm rolling on microstructure evolution and mechanical properties of a Ni–W–Co–Ta medium-heavy alloy

Abstract

The microstructure and mechanical properties influenced by warm rolling in a Ni–W–Co–Ta medium-heavy alloy (MHA) is studied in this work in order to explore the optimal processing-microstructure-property paradigm. The results show that the initially equiaxed grains evolves into a fibrous structure, aligned with the rolling direction, as the rolling progresses. Texture analysis reveals a transition from Brass-type component to a mixed texture component of Brass-type and Copper-type with increasing deformation. Concurrently, dislocation density rise, and nano deformation twins and precipitation of Ni₄W take place. The strength is significantly enhanced. However, the trade-off between strength and ductility still persists. An optimal combination of strength and ductility has been achieved at a 50 % rolling deformation. These demonstrate that warm rolling is an effective processing route for manufacturing high-strength and still ductile MHA.