Simultaneously\nEnhanced Damping and Stiffness of Amorphous\nDiaphite

High-performance\ndamping materials are crucial for numerous applications,\nyet traditional materials often face a fundamental trade-off between\nthe damping properties and stiffness/strength. Since damping properties\nof material rely on its inner viscoelastic energy dissipation, it\nis antagonistic for damping material sustaining high mechanical loads.\nRecently, an amorphous carbon known as amorphous diaphite (a-DG) was\nreported, featuring a heterogeneous two-phase composition of nanodiamonds\nand disordered multilayer graphene (ND/DMG). The a-DG demonstrated\ndiverse microstructure topologies and integrated characteristics,\nmaking it a promising candidate for achieving efficient energy dissipation\nin high-stiffness/strength materials. Herein, we conducted atomistic-based\nsimulations to elucidate the mechanical and damping properties in\na-DGs with tunable two-phase structures. Utilizing cyclic loads and\nVoigt–Reuss–Hill theory, we found that a-DGs exhibit\nsurpassing stiffness and damping capabilities simultaneously, with\nexcellent specific elastic modulus due to lightweight (2.39–3.25\ng/cm<sup>3</sup>). The distinguishing performance is attributed to\na balanced combination of flexible DMG and stiff ND grains, which\ncan be tuned through manifesting the hybridization. Specifically,\nthe concentrated shear strains, phase transformation and interfacial\nhybrid bond conversion significantly enhance internal friction through\nvarious relaxation mechanisms, while ND grains ensure high stiffness\nthrough blocking the propagation of shear bands. The insights obtained\nhere should provide theoretical support for the design and application\nof high-performance damping materials, opening up an enticing perspective\nfor investigating other amorphous carbons.