Investigation of tool speed effect on fracture toughness of Aluminum Alloy 2024-T351 friction stir weld joints by means of digital Shearography

The present paper examines the influence of rotational and traverse speed of tool on fracture toughness in Friction Stir Welding (FSW) of the Aluminum alloy plates 2024-T351 which are connected in a butt jointed way. Fracture behavior was studied based on standard test method (ASTM-E399) and also Shearography optical technique, in CT welded specimens. Stress Intensity Factor (SIF) is determined by Simultaneous extraction of Sherographic fringes using the new algorithm of image processing. From the fracture toughness results, it was found that the welding process decreases the joints fracture toughness 18-49% with respect to the base metal. The lower traverse speed cause to low fracture toughness and at higher traverse speeds or rotational speeds of the tool the fracture toughness is lower.