Stereographical and characterization analysis of nano yttria-dispersed tungsten heavy alloys: Impact on particle size and Y-W-O complex oxide formation
Year: 2025
Type: article
Abstract: The present study investigates the influence of nano-Y₂O₃ (0.25–0.75 wt%) additions on the microstructural evolution of a tungsten heavy alloy (WHA) composed of 93 wt% tungsten, with a fixed Ni/Co binder ratio of 9. The precursor powders of Ni, Co, and Y₂O₃ were subjected to high-energy ball milling to produce an oxide-dispersion-strengthened (ODS) matrix, which was subsequently blended with tungsten via low-energy ball milling. The resulting composite powders were consolidated through cold isostatic pressing and sintered at 1438 °C for 1 h. The processed ODS-W-Ni-Co alloys achieved a relative density exceeding 99.7 % of the theoretical value. Microstructural analysis confirmed the formation of a W-Y-O complex oxide phase, characterized by core-shell structures and particle coarsening phenomena. These structural transformations substantially influenced grain morphology, growth kinetics , and overall microstructural refinement. Notably, the incorporation of 0.75 wt% Y₂O₃ increased the solid-liquid interfacial energy to 744.44 MJ/m 2 , albeit inducing anisotropic interfacial energy distributions. High-resolution transmission electron microscopy (HR-TEM) revealed a semi-coherent γ-Ni/Y₂O₃ interface with a lattice mismatch parameter of 0.056, which is indicative of enhanced interfacial bonding . The presence of this semi-coherent interface is proposed to improve interfacial strengthening between W grains and the γ-Ni binder phase, contributing to microstructural stability and potential mechanical property enhancement.
Authors: N. Siddharthan, S. Kumaran, Ming-Wei Wu, C. Pandi Selva Durai, P.V. Sathya Narayana, Gandi Vivek Kumar Raja
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,310
OpenAlex ID: W4408932748