High mechanical performance in W-Gd2O3 composites achieved through sintering optimization and microstructural refinement

W-Gd 2 O 3 composites with different Gd 2 O 3 content have been fabricated via hot-press sintering at sintering temperatures of 1600 °C-1900 °C. This work presents the first systematic investigation of Gd 2 O 3 grain boundary segregation in a W matrix and its remarkable grain-refining effect, achieving an average grain size of 0.73 μm. Adding Gd 2 O 3 improves the sintering behavior of the W-Gd 2 O 3 composite. When the sintering temperature is 1800 °C, the relative density of W-Gd 2 O 3 composites can achieve over 99%. Gd 2 O 3 as a dispersion-strengthening phase significantly enhances the mechanical properties of W-based composites. Gd 2 O 3 particles, preferentially located at W grain boundaries, effectively suppress grain growth, leading to significant grain refinement and enhancing mechanical properties. The W-Gd 2 O 3 composite sintered at 1800 °C exhibits optimized mechanical properties when the Gd 2 O 3 content is 9 wt.%. The corresponding flexural strength and fracture toughness can reach 1149 MPa and 12.17 MPa‧m 1/2 , respectively.