Alloying mechanisms of binary immiscible systems based on tungsten-copper composite materials

To gain a deeper understanding of the alloying mechanism of binary immiscible systems, taking W-Cu composite materials as an example, we utilized laser texturing and surface nano-activation technology to prepare high-strength W-Cu joints. This study combines theoretical calculations and experimental approaches to investigate these mechanisms, utilizing thermodynamic modeling, energy-dispersive X-ray (EDX) analysis, and molecular dynamics (MD) simulations. Our proposed thermodynamic model introduces an innovative approach, translating surface energy into thermodynamic calculations, thereby offering broad applicability to various immiscible metal systems. The results demonstrate diffusion anisotropy at the W-Cu interface, where the diffusion of Cu into W is primarily driven by vacancy mechanisms. MD simulations further reveal that surface roughness significantly lowers the temperature threshold for Cu amorphization, a finding corroborated by in-situ transmission electron microscopy (TEM). This work deepens our understanding of alloying in immiscible metal systems and offers valuable insights for optimizing high-performance W-Cu composites in engineering applications.