Effects of extrusion on microstructure and tensile properties of 3D network structured TiBw/Ti60 composites fabricated by reaction hot pressing

In situ TiB whisker reinforced Ti60 matrix composites (TiBw/Ti60) have been successfully fabricated by reaction hot pressing. The effects of extrusion on microstructure and tensile properties of TiBw/Ti60 composites were investigated. The microstructure results show that the original equiaxed network microstructure of the as-sintered TiBw/Ti60 composites was extended after extrusion deformation, while the TiB whiskers had aligned along the extrusion direction. Moreover, the TiBw clusters of the as-sintered TiBw/Ti60 composites with the higher volume fraction of reinforcement can be effectively dispersed by extrusion deformation. The testing results reveal that the as-sintered TiBw/Ti60 composites show a little improvement in strength but a remarkable reduction in elongation relative to the momolithic Ti60 alloy at room temperature. Both the tensile strength and the ductility of the composites can be significantly increased by the subsequent extrusion deformation. Moreover, the ultimate tensile strength of the as-extruded 3.4 vol.% TiBw/Ti60 composites is increased by 21.9% compared with that of the as-extruded Ti60 alloy at 600 °C.