Solute segregation and nanoparticle dispersion induced super high stability in a bulk nanocrystalline W-based alloy

Improvement of the stability of nanocrystalline (NC) materials is always a challenge. In this paper, the high thermal stability is achieved in a representative NC W alloy by combining nano-segregation of Ti solute to W grain boundary (GBs), and in-situ formation of nano Ti–Zr–O particles, which provide both thermodynamic and kinetic stabilization effects through solute dragging and particle pinning. The recrystallization temperature of this bulk NC W alloy reaches up to 1600 °C, and these nanometric microstructures maintain stable under a long-time and high-temperature ordeal up to 1200 °C for 120 h. And its microhardness and micro-compressive yield strength are ∼17.0 and 5.14 GPa, respectively. In addition, this bulk NC W alloy has high irradiation stability due to the high densities of stabled GBs and phase boundaries. This work demonstrates the possibility of attaining high-stability bulk NC materials in terms of segregation of solutes at GBs and in-situ formation of ultrafine nanoparticles with a coherent interface with the W matrix.