Friction Stir Welding of Fibre-Reinforced Titanium Composites for Aerospace Structures

Abstract

Composite materials consisting of a titanium alloy reinforced with continuous silicon carbide fibres, called TiSiC, are currently being investigated to enhance performance for applications where titanium alloys are used. Conventional fusion welding techniques create difficulties due to the detrimental impact of high temperature on the fibre/metal interfaces. This study describes the application of stationary shoulder friction stir welding (SS-FSW) technique to join TISIC components to monolithic titanium. Microscopic investigations had shown flaw-free welding, until the SSFSW tool started to mechanically interact with the SiC fibres. When subjected to tensile testing, the weld properties were superior to the parent monolithic titanium. The comprehensive investigation of fracture toughness, residual stress and fatigue properties of the weld components are presented and potential advantages discussed.