High-performance titanium-based composite strengthened with in-situ network-distributed 3D reinforcements

摘要

Ti-based composite with in-situ 3D nano-reinforcements consisted of boron nitride nanosheets (BNNSs), titanium boride (TiB) nanowires and titanium diboride (TiB_2) nanoparticles was prepared in a facile way-blending spherical Ti powder and BNNSs via low-energy ball milling and then consolidating the composite powder by spark plasma sintering. It has an excellent combination of strength and ductility: the composite with 0.5 vol% BNNSs exhibits high tensile strength of around 715.1 MPa and excellent toughness of 115.2 MJ/m~3, which is 73.4% higher and 16.6% lower than those of pure Ti, respectively. The strength enhancement is mainly attributed to the interlocking structure formed by TiB_2 nanoparticles and BNNSs, which increases the dislocation density and doubles the theoretical interfacial shear strength limit. The considerable ductility arises from the crack blocking brought by the 3D network.