Mechanical characterization of the friction stir welding joints of Al-Li alloys for aeronautical applications
Structural design for safety critical components,as the case of airframes,requires comprehensive characterization of the materials and joints properties.This characterization needs to take into account a large amount of variables required for accurate design to ensure structural integrity during the different phases of the product life cycle of an aircraft.One of the most important variables in this characterization is fatigue behavior due to the cyclic loads during the life of an airframe,which decrease significantly the structural strength.The application of welding in aeronautical structures to replace riveted joints is an attractive option since it allows joints with less stress concentration points and might be applied efficiently without overlapping the two joining parts (with a butt-joint configuration),reducing the joint weight.This weight reduction can have a small impact in production costs,but has a huge impact in the life cycle costs.However,the application of welding has been limited due to two major reasons:low crack arrest capability in welded joints compromising the structural integrity,and the weldability of the aluminum alloys used in the airframes.Several welding processes can now deal with the low weldability of hardened precipitated aluminum alloys,although the low crack arrest capability persists and is an obstacle for massive adoption of this joining process.Some of these issues are mitigated with the application of newer joining processes that require less heat input and are more trustworthy.Friction stir is the most appealing welding process in aeronautical structures since it has been shown to produce joints with excellent properties when applied to aluminum alloys and can deal with hardened precipitated aluminum alloys,since it is a semi-solid state process.This communication presents a mechanical characterization of friction stir welds of last generation aluminumlithium alloys,with potential applications in aeronautical and aerospace components.This mechanical characterization was preceded by welding parameter calibration and comprised a program of experimental tests of welded joints.Mechanical characterization with crack initiation and fatigue crack growth were included in this study for an enhanced assessment of these alloys behavior.
aluminium alloys friction stir welding fatigue characterizations material properties damage tolerant design
S.M.O.Tavares J.F.dos Santos P.M.S.T.de Castro
Department of Mechanical Engineering,Faculty of Engineering of the University of Porto,Portugal Helmholtz-Zentrum Geesthacht GmbH,Institute of Materials Research,Materials Mechanics,Solid State Jo
国际会议
International Conference on Airworthiness & Fatigue -7th ICSAELS Series Conference(大飞机安全性能与疲劳国际会议)
北京
英文
65-70
2013-03-24（万方平台首次上网日期，不代表论文的发表时间）