Comparative Study on Microscopic, Physical and Mechanical Properties of Conventional and Spark Plasma Sintered Nano-TiO₂-Dispersed Zirconium-Based Alloys

In this study, nano-TiO₂ (1.0–2.0 wt.%)-dispersed Zr-based alloys with nominal compositions: 45Zr–30Fe–20Ni–5Mo (alloy 1), 44Zr–30Fe–20Ni–5Mo–1TiO₂ (alloy 2) and 44Zr–30Fe–20Ni–4Mo–2TiO₂ (alloy 3) are synthesized by mechanical alloying in a dual-drive planetary ball mill followed by powder consolidation with conventional sintering at 1400 °C/spark plasma sintering at 900–1000 °C. For microstructural and phase analysis of mechanically alloyed powders and consolidated products, XRD, SEM/EDS and TEM studies were carried out. Density measurement and mechanical property (compressive strength, hardness and wear) characterization were also carried out. X-ray diffraction and TEM analysis reveal formation of different intermetallics of 10–30 nm size along with TiO₂ (10–20 nm) throughout the matrix of the consolidated samples. Alloys consolidated by spark plasma sintering displayed high levels of compressive strength (825–1240 MPa) and hardness (10.38–16.85 GPa) which was 1.5–2 times higher than that was obtained in conventional sintering. Addition of TiO₂ helps in enhancement of mechanical properties, and effect was more prominent with 2.0 wt.% TiO₂.