Investigating the strength of Ti/TiB interfaces at multiple scales using density functional theory, molecular dynamics, and cohesive zone modeling

Titanium/titanium boride (Ti/TiB) composites are interesting technological materials with prospective appli-cations in the aerospace, automotive, and biomedical industries. However, not much has been studied about the failure mechanisms of these composites. This article thoroughly investigates the adhesion and strength of two well-known Ti/TiB interface variants formed during the production of Ti/TiB composites below and above 910 degrees C, respectively. The studies were carried out using different theoretical methods at multiple scales, including density functional theory (DFT), molecular dynamics (MD), cohesive zone modeling (CZM), and the finite element method (FEM). First, we employed DFT to investigate the interfacial adhesion and strength of the selected planes. Then, MD simulations were utilized to study the misfit dislocation networks and derive inter-facial CZMs for FEM modeling and simulation of composites. Our FEM simulations showed that the Ti/TiB interface has sufficient strength to transfer the shear load from Ti to TiB without debonding at room temperature. The results have confirmed the same phenomenon observed in some experimental studies and interpreted this phenomenon from a multiscale point of view. The research findings can be used in quantifying the failure stress of TiB whiskers directly from tension tests on Ti/TiB composites by ruling out the possibility of interface debonding.