• Vilaça, P.
• Infante, V.
• Vidal, Catarina

Abstract

<p>One major trend in aerospace industry to accomplish highly demanding cost reduction programs and improvement of structural efficiency is the substitution of built-up structures which are riveted together. The solid state Friction Stir Welding (FSW) process enabled to accomplish these objectives including new design concepts to be applied on feasible joints between advanced lightweight metallic materials that previously were difficult or even impossible to weld. The resultant welded joints show a micro-structure finer than that of the parent material with relatively low residual stresses. The fine-grained stirred zone presents typically good strength properties and ductility. The assessment of the fatigue resistance effect of improvement techniques applied to the root of FSW welded specimens are investigated in order to provide indication on the correct welding procedure to be applied during production of friction stir welded aeronautic structures. This paper presents the results obtained on a fatigue study on the rehabilitation of friction stir butt welds of the aerospace aluminum alloy AA2024-T351. Fatigue data is presented in the form of S-N curves. Detail metallographic characterization of weld zone, hardness distribution at different zones of the weld region and the fracture surfaces are also presented. Results show fatigue resistance of improved welded specimens overcoming base material.</p>

Topics

• impedance spectroscopy
• surface
• aluminium
• strength
• fatigue
• hardness
• ductility