Modeling, microstructure, and mechanical properties of dissimilar 2017A and 5083 aluminum alloys friction stir welds

Abstract

Dissimilar aluminum alloy plates of 2017A-T451 and 5083-H111 were friction stir welded in a butt joint configuration along the longitudinal direction. Welding trials demonstrated that placing 5083 on the advancing side enhanced material flow and consequently formed a larger weld nugget. Numerical simulation supported this observation through analysis of volumetric flow rates through reference planes surrounding the stir zone. The analysis also suggests that the weld configuration that results in a decreasing temperature-dependent flow stress in the weldment from the leading edge of the tool to the trailing edge will maximize material flow in dissimilar friction stir welding welds. The decreasing flow stress promotes material flow along the retreating side of the tool as flow conditions necessarily become easier from the front to the back. Regardless of its position during welding, however, 2017A alloy dominated the nugget region. In either weld configuration, alternating bands of 2017A and 5083 with similar grain sizes (approximately 10 µm) comprised the weld microstructure. Within the nugget, numerous second-phase particles as well as dislocations occurring as single dislocations or in the form of dislocation tangles or walls (low angle grain boundaries) were present. The relatively high dislocation density observed in both alloys suggested that recrystallization was incomplete. Hardness mapping revealed an asymmetric variation of hardness across the weld centerline that strictly corresponded to the distribution of particular alloys within the nugget. During tensile testing, the AS 5083-RS 2017A configuration failed under ductile shear rupture occurring in the base 5083 material far from the weld. For the opposite configuration, the tensile samples ruptured perpendicular to the load axis exactly on the border between the nugget and the thermomechanically affected zone on the 2017A alloy side.

A review of microstructural changes occurring during FSW in aluminium alloys and their modelling

“…We have also to mention that no clear detail on precipitate evolution in dissimilar welding have been reported in previous chapters. Indeed, literature review seldom report simulations of precipitate evolution when two aluminium grades or even metallic alloys are considered despite the large interest of dissimilar welding as investigated by Hamilton et al (2019). In a recent review article, Patel et al (2019) highlight also the advantages, difficulties and challenges associated to dissimilar aluminium welding in FSW processes.…”

“…In recent years, the scientific community seems particularly interested in the study of dissimilar welding as shown by Hamilton et al (2019). Indeed, FSW process has the advantage to develop welding on alloys usually considered as non-weldable until now.…”

Flow, process forces and strains during Friction Stir Welding: A comprehensive First principle approach

“…Numerical simulation concerning temperature and flow stress in the stir zone for dissimilar FSW has been recently published. 21 However, the yet unaddressed modelling of process forces for dissimilar FSW has been included and experimentally validated in the current analysis.…”

Investigation of forming limit diagram and mechanical properties of the bimetallic Al/Cu composite sheet at different temperatures which fabricated by explosive welding

“…4 Some benefits of using bimetallic composites are increase wear resistance, lighter weight, appropriate thermal and electrical conductivity, lower spring back and better formability of the sheet. 5–7…”