Effects of nanosized particles on microstructure and mechanical properties of an aged in-situ TiB2/Al-Cu-Li composite

Abstract

The effects of nanosized TiB2 particles on microstructural and mechanical properties of the hot extruded in-situ TiB2/Al-Cu-Li composite after T6 heat treatment are quantitatively evaluated by using scanning electron microscopy, transmission electron microscopy, electron backscatter diffraction technique and X-ray diffraction. Most TiB2 particles are aggregated together to form the particle bands. The composite develops the typical fiber textures, <111> and <l00> paralleling to extruded direction, while the matrix alloy only develops weak <111> and <113> textures. The intensity and volume fraction of major texture components can increase significantly with the addition of TiB2 particles. Due to the introduction of TiB2 particles, T1 and S phases not only have higher number density, but also are smaller. In addition, the T1 phases can connect with each other to form a continuous network in the composite. The θ’ phase, identified in matrix alloy, is rarely observed in the composite. The yield strength and ultimate tensile strength of composite have increased by 248 MPa and 152 MPa compared with matrix alloy, respectively.