On the Structure and Mechanical Properties of Multilayered Composite, Obtained by Explosive Welding of High-Strength Titanium Alloys

Abstract

One of the ways to simultaneously increase the strength and the fracture and impact toughness of structural materials is by producing multilayered materials. In this paper we discuss the structure and properties of a seven-layer composite obtained by explosive welding of high-strength titanium alloys. The structure of the composite was characterized using light microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). At the interfaces between plates, formation of waves and vortices was observed. The wave formation is discussed with respect to the kinetic energy loss. The vortices consisted of a mixture of two alloys and possessed a martensitic structure comprising α′ and β phases of titanium. Localized plastic deformation occurred along the interfaces during explosive welding by formation of shear bands. The most intensive shear banding occurred in the vicinity of the upper interfaces. The local hardness at the interfaces increased due to the formation of the quenched structures. The interfaces between titanium alloys positively influenced the impact toughness of the composite, which increased in comparison with that of bulk titanium alloys by a factor of 3.5. The strength characteristics of the composite remained at the same level as that of the bulk material (1100–1200 MPa).

Keywords

• explosive welding
• α + β titanium
• shear bands
• vortices
• impact toughness