Three dimensional interfacial design for synergistic enhancement of strength and uniform elongation in TA15 composites reinforced with trace BNNSs

Addressing the prevalent strength-ductility trade-off in discontinuously reinforced titanium matrix composites (DRTMCs), this study presents a novel approach by fabricating BNNSs/TA15 composites reinforced with a minimal amount of two-dimensional (2D) boron nitride nanosheets (BNNSs) through a combination of low-temperature, fast hot-press sintering and hot-rolling processes. The in-situ formation of TiB through solid-state interfacial reactions, which epitaxially grows from the BNNSs into the titanium matrix, results in the creation of a three-dimensional (3D) TiB@BNNSs interfacial architecture. The incorporation of BNNSs effectively refines the microstructure of the titanium matrix, TiB@BNNSs interfacial structure strengthens the interfacial bonding between BNNSs and titanium matrix, which effectively relieves the localized stress concentration during tensile process, and can coordinate the deformation between BNNSs and the titanium matrix. The quantitative analysis of the strengthening mechanism indicates that the TiB@BNNSs interface is capable of exerting excellent load-transfer strengthening effects. The 0.05 wt% BNNSs/TA15 composite demonstrates a synergistic improvement, with ultimate tensile strength and uniform elongation increasing by 21.24 % and 3.31 %, respectively, compared to the TA15 matrix, achieving an exceptional balance of strength and ductility. This work provides a new strategy for the development of high-performance DRTMCs.