Characteristics of the mechanical behavior of a near-alpha multilayer laminate under impact loading

Titanium alloy Ti-6Al-2Zr-1.2Mo-1.3V is widely used in various branches of modern engineering. This alloy is used for the manufacturing of wing skins, hulls and blades of highly loaded gas turbine engines by diffusion bonding (DB). Moreover, DB can be used to easily manufacture multilayer materials and composites. From a mechanical point of view, the considerable interest in multilayer materials is due to the possibility of achieving improved dynamic properties. In addition, the degree of mechanical anisotropy in these materials can be easily controlled. This study presents the results of microstructural investigation, quantitative assessment of impact fracture characteristics and fractographic analysis of a fracture surface of a diffusion bonded multilayer material consisting of thirteen layers of Ti-6Al-2Zr-1.2Mo-1.3V alloy. Diffusion bonding of anisotropic sheets assembled in a package so that the angle between the rolling directions in the neighboring sheets was 90o made it possible to obtain a multilayer material with isotropic mechanical properties. The impact strength of an obtained multilayer material in a crack divider orientation was about 1.6 MJ /m(2). A crack propagation energy was approximately 4 times higher than a crack initiation energy. Fracture of this material was accompanied by formation of delamination. A fracture surface had a dimpled ductile character.