Multiplied bending ductility and toughness of titanium matrix composites by laminated structure manipulation

Abstract

In order to improve ductility and toughness, ductile Ti layer was introduced into TiB reinforced Ti-6.58Al-1.76Zr-0.89Mo-1.04V (TiB/TA15) composite and constructed a laminated structure. The bending ductility and toughness of the as-fabricated laminated composites were tripled compared with the TiB/TA15 composite. Elements diffusion between adjacent layers during sintering process strengthened the ductile Ti layer, and provided extra back stress strengthening effect. Crack blunting and crack deflection by the ductile Ti layer also contributed to the property enhancement. The laminated composite exhibited an interface bonding strength of 870 MPa. As a result, no interface delamination was observed, which ensured that the ductility of the introduced Ti layers were fully tapped. Increasing the TiB/TA15 layer thickness enhanced the bending strength but deteriorated the ductility and toughness. In addition, sandwich structured composites were also prepared, and the stacking sequence exhibited noticeable effect on the bending behaviors of these composites. This impact was mainly attributed to the altering of fracture sequence of layers in the specimen. For sandwich structured composites, the change of layer thickness ratio and stacking sequence resulted in various profiles of bending curves