Fracture mechanism of a high tensile strength and fracture toughness Ti6Al4V-TiAl laminated composite

摘要

Ti6Al4V (wt.%)-Ti43Al9V0.3Y (at.%) laminated composites were fabricated from as-forged TiAl and commercial Ti6Al4V sheet by hot-pack rolling, and the microstructure of composites were investigated. The results showed that the target laminated composites were achieved by reaction and diffusion bonding. A defect free interfacial region was observed indicating that The Kirkendall effect was successfully avoided by substituting Al metal foils with Ti43Al9V alloy sheets. The microstructure, from the Ti6Al4V side to the Ti43Al9V side, had four different microstructure regions which are alpha+beta, alpha(2), alpha(2)+gamma+beta(2) and beta(2)+gamma, respectively. The tensile properties and fracture toughness of composites were examined. It was noteworthy that the composites not only retained high tensile properties in both room temperature and 700 degrees C, but also possessed high fracture toughness. It was also proved that the unique mix-phase interfacial region obtained by hot-pack rolling has a great contribution to the improvement of the properties of composites and strengthening-toughening mechanism were clarified profoundly. (C) 2019 Elsevier B.V. All rights reserved.