ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Residual stress fields may be rather frequently observed in several mechanical and structural parts,usually as a result of the manufacturing and joining techniques adopted. Their effects on materialperformances can be quite different, going from highly detrimental to beneficial, according to theirdistribution and to the acting material damage mechanisms (fatigue fracture, brittle or ductilefailure, corrosion,…).Residual stresses are produced in welded structures by thermal expansion, plastic deformation andshrinkage during cooling. The amount of constraints determines the level of residual stress.Friction Stir Welding (FSW) is a quite new joining technique particularly for aluminium alloysdifficult to fusion weld. Since conventional FSW showed its limits, Bobbin Tool technology hasbeen developed. These both types of welds produce low-distortion of high quality (even no postwelddistortion) and relevant residual stresses.The residual stresses of the aerospace material 6056-T78 aluminium alloy Friction Stir Weldedsheets have been analysed on various tempers in accordance with these two different technologies.The effects have been investigated parallel and orthogonal to the weld direction. By means of localor global heat treatments, the residual stress state can be generally reduced or changed from tensileto compressive stresses on surface; in that way, the different heat aging conditions T78 as-weldedand post-welded are checked in this study. This paper presents the method used, the measurementsof this fatigue damage and their consequences on the fatigue life performance of structuralmaterials
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/13/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.519-521.1089.pdf
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