Enhanced strength and ductility of boron nitride nanosheet reinforced cu composites through constructing an interfacial three-dimensional structure

To address the poor wettability and weak interface bonding between boron nitride nanosheet (BNNS) and Cu, BNNS/CuTi composites were prepared through matrix microalloying by adding 1 wt% Ti. Solid-state interfacial reactions resulted in the formation of TiN transition layers and TiB whiskers (TiBw), collectively constructed a BNNS-(TiN&TiB)-Cu interfacial three-dimensional structure (I-3DS). The coherent I-3DS significantly reduced the interfacial energy, improved the interfacial stability, and achieved a favorable combination of strength and ductility in BNNS/CuTi composites. The 0.1 wt% BNNS/CuTi composite achieved an ultimate tensile strength (UTS) of 485 MPa, representing increases of 114 % and 62 % over pure Cu and 0.1 wt% BNNS/Cu composite, respectively. The interlocking structure formed by I-3DS and Cu doubled the theoretical interface shear strength limit and improved load transfer efficiency. This study offered new insights into the innovative design of high-performance Cu matrix composites (CMCs) by constructing I-3DS.