Study on microstructure and mechanical properties of W-Ni3Al alloys prepared by ball milling and two-step sintering

In this paper, W-Ni3Al alloys with the different Ni3Al contents were prepared via ball milling and two-step sintering processes. The relationship of Ni3Al contents, microstructural evolution, and mechanical properties of W-Ni3Al alloys were also clarified. The results show that the milled powder has a lamellar structure and cold welding phenomenon. This structure encloses a small amount of ethanol, and this causes an Al2O3 phase to form when it undergoes an oxidizing reaction of Ni3Al with oxygen in ethanol during ball milling and drying. The W-rich phase is the network structure, and this structure is finer and denser with an increase in Ni3Al contents as a result of the grain refining effect of Al2O3 particles and the densification effect of liquid sintering. Under a load, the Al2O3 particles at the interface of W/binder phases increase the resistance of crack growth and compressive strain, which improves the mechanical properties and deformability of W-Ni3Al alloys. The Ni3Al binder provides a new strategy for improving the mechanical properties of tungsten alloys.