Nature Sustainability, Published online: 12 May 2026; doi:10.1038/s41893-026-01822-x The fabrication of silk materials typically requires large amounts of solvents. Now, a simple thermomechanical strategy enables natural silk fibres to be directly fused into strong, multifunctional materials without solution processing. By preserving silk’s hierarchical structure, this approach, which is amenable to scale-up, offers a sustainable route towards high-performance bio-derived materials.