Fabrication and Characterization of Tungsten-Based Hard Materials by Novel Mechanical Alloying and Spark Plasma Sintering Methods

Abstract

The influence of Ir and Y₂O₃ on the densification, microstructure, and wear characteristics of pure W-based alloy/composite was examined. The precursor powders, including W, Ir, and Y₂O₃, underwent mechanical alloying for 30 hours, resulting in two compositions: W–1.5 wt.% Ir and W–1.5 wt.% Ir–2 wt.% Y₂O₃. Subsequently, the prepared mixtures were subjected to spark plasma sintering at a temperature of 1650 °C for 5 minutes, with a simultaneous application of 50 MPa pressure. X-ray diffraction, scanning electron microscopy combined with energy dispersive spectroscopy, a micro-Vickers hardness tester, and two-dimensional optical profilometry were employed to analyze the synthesized powders, along with the consolidated and worn samples. Results indicated that the W–1.5 wt. % Ir-2 wt. % Y₂O₃ composite produced a highly dense sample characterized by the smallest grain size, superior micro-hardness, and enhanced wear resistance. The composite achieved values of up to 98% density, 3.6 µm grain size, 4.9 GPa HV₀.₅ hardness, and 2.5 × 10⁻⁵ mm³/Nm wear resistance, in contrast to pure tungsten, which exhibited 83.1% density, 6.6 µm grain size, 1.9 GPa HV₀.₅ hardness, and 6.2 × 10⁻⁵ mm³/Nm wear resistance. Thus, both Ir and Y₂O₃ have been recognized as effective additives that can enhance the consolidation and refinement of tungsten's microstructure under current mild processing conditions. This advancement not only makes these materials commercially viable but also enhances their performance in a range of demanding applications, such as fusion, military, tooling, electrode manufacturing, and coatings.