Epitaxial growth of rare-earth yttrium on nanosheets to form semicoherent interface in zinc implant

Molybdenum disulfide (MoS2) nanosheet as nano reinforcement exhibits great advantages in zinc (Zn) implant due to its coordinated crystal slip and grain boundary strain effect. Nevertheless, the poor interface bonding restrains the coordination effect of MoS2. In this work, rare earth yttrium (Y) was used to epitaxial grow on the vacancy nucleation sites of MoS2 plane through a gas phase reduction method, and then introduced into Zn to improve their interface bonding. On one hand, rare earth Y could form a semicoherent interface with Zn due to the similar atomic arrangement and small lattice misfit between (101)Y plane (0.272 nm) and (002)Zn plane (0.248 nm). On the other hand, it could be tightly integrated together with sulfur element of MoS2 via covalent bond. As a result, the plastic strain of composites was improved from 6.1 % to 10.45 %. Simultaneously, the fracture energy was also increased to 201 × 103 J/m2, since rare earth Y considerably promoted load transfer efficiency from Zn matrix to MoS2 and thereby significantly activated slip systems. Encouragingly, the mechanical strength of the Zn-based biocomposite simultaneously reached 273.3 ± 10.9 MPa due to load transfer strengthening and grain refinement.