High-performance spherical W-Cu composite powders for additive manufacturing via spray granulation and cold isostatic pressure sintering

Abstract

Developing spherical W-Cu composite powders offers a promising solution for achieving additive manufacturing to prepare W-Cu composites with finer microstructures and superior properties. However, the melting point difference and poor wettability of W and Cu hinder traditional powder preparation methods. Spray drying with sintering densification provides an efficient, cost-effective, and eco-friendly approach to producing dense spherical powders for additive manufacturing. This study developed spherical W-Cu composite powders for additive manufacturing using WO₃ and CuO as raw materials. Initially, a spherical W-Cu precursor powder was synthesized from WO₃ and CuO via spray-drying granulation. The precursor powder was then subjected to a three-stage reduction procedure. Finally, high-performance powders were produced via cold isostatic pressing and high-temperature sintering with ultrafine WO₃ as the sintering barrier. The resulting powders exhibited high sphericity, good dispersion, high densification, and fine-grained microstructures with uniform elemental distribution, as well as excellent fluidity (11.6 s/50 g), high loose apparent density (7.65 g/cm³), and low oxygen content (225 ppm), rendering them ideal for additive manufacturing. Laser-directed energy deposition (L-DED)-fabricated parts exhibited outstanding properties, including high densification (relative density 96.2 %), excellent tensile strength (512.57 MPa), hardness (260.6 HV_0.5), electrical conductivity (37.93 % IACS), and thermal conductivity (215.35 W/mK), comparable to the W-Cu parts produced using conventional processes. The proposed method offers a promising approach for the development of advanced materials tailored to AM technologies.