Abstract
In this work, two simple but effective strategies were proposed to optimize friction-stir welding of 6061-T6 aluminum alloy. The first one involved an optimization of welding variables to provide a combination of a relatively high welding temperature and the shortest possible thermal cycle during friction-stir welding. This inhibited precipitation coarsening in the heat-affected zone and resulted in considerable residual stress. Accordingly, the produced welds exhibited excellent strength characteristics under static and cyclic loading conditions. The second method was based on the application of the standard postweld T6 tempering. To avoid the abnormal grain growth, which usually occurs during solutionizing of aluminum friction-stir welds, a prestrain rolling was employed prior to the material tempering. This promoted an activation of recrystallization processes during subsequent heat treatment, thus suppressing the abnormal grain growth.
Highlights
The particles coarsening observed in the heat-affected zone is often considered as the most detrimental effect of friction-stir welding, because it could not been recovered during standard postweld aging treatment [5, 28]
That an optimized friction-stir welding, which involves a combination of a high tool rotational rate and a high welding speed, may improve the joint efficiency of the friction-stir welded heat-treatable aluminum alloys
Significant microstructural changes occurring during friction-stir welding as well as during subsequent heat treatment may result in degradation of mechanical properties of heat-treatable aluminum alloys
Summary
Due to attractive combination of low density, good service properties and reasonably low cost, heat-treatable aluminum alloys are widely used in transportation industry. A significant problem of such materials is a relatively poor weldability by conventional fusion techniques. This necessitates using a riveting approach for manufacturing of large-scale aviation structures increasing their total weight and cost and degrading performance. In this regard, friction-stir welding (FSW), an innovative technology, is widely considered as a very promising candidate for joining of these alloys [1, 2]. Some of the most important results are briefly summarized below
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call