Synergetic strength-ductility enhancement of bcc W wires by coherent oxide nanocomposites pinning effect

Abstract

Thin tungsten (W) wires are among the most promising candidates for sawing industrial hard materials, such as wafers and sapphire. However, their limited tensile strength restricts the further reduction of wire diameter, resulting in increased material waste and reduced cutting precision. In this study, we report a thin lanthanum (La)-doped W wire fabricated through La oxide addition assisted ice-bathed non-slip drawing method, exhibiting an ultrahigh tensile strength exceeding 6.92 GPa and a ductility of 4.2 %, realizing improvements of 30.6 % and 33.3 % than pure W wires. This developed wire achieves the highest strength among reported W-based materials while simultaneously realizing a synergetic enhancement in both strength and ductility. Statistical analysis-assisted atomic-resolution imaging and molecular dynamics (MD) simulations reveal that hexagonal close-packed (hcp) La oxide precipitates pin at the grain boundaries and form a coherent interface with the body-centered cubic (bcc) W matrix, inducing nano twins, lattice distortion and dislocations within the W matrix, thereby altering its plastic deformation mechanism. The pinning effect enhances grain boundary plasticity and facilitates uniform deformation, leading to the simultaneous improvement of strength and ductility. This work provides a promising prototype for the development of high strength-ductility thin wires and demonstrates a scalable approach for industrial production.