CHARACTERISTICS OF STRUCTURAL STRENGTH OF D16T ALLOY WELDED JOINTS, PRODUCED BY FRICTION STIR WELDING.

A series of research was performed to study the characteristics of structural strength of butt joints of aluminium alloy D16T 2 mm thick, produced by friction stir welding. Features of weld formation and degree of metal softening in the zone of the produced permanent joint were analyzed. Mechanical testing of welded joint samples was performed at static and cyclic loading. Diagrams of fatigue crack growth rates in the base metal, heat-affected zone and thermomechanical impact zone, on the boundary of these zones and in the weld metal were plotted. It is shown that the characteristics of cyclic crack resistance of weld metal of these joints are more than two times higher than the respective values for base metal that is indicative of the good prospects for application of friction stir welding in fabrication of critical structures from D16T alloy. 19 Ref., 8 Figures. [ABSTRACT FROM AUTHOR]