Mechanical properties and microstructural characterization of extrusion welds in AA6082-T4

Document Type

Article

Publication Date

11-2004

Department

Department of Mechanical Engineering-Engineering Mechanics

Abstract

Microstructural observations of extrusion welds in an A-pillar made of AA6082-T4 revealed that the observed extrusion weld is a composite of a seam weld (longitudinal weld) and a charge weld (transverse weld). To determine the mechanical properties of this weld region, tensile specimens were prepared with the weld located at 0°, 45°, and 90° to the tensile axis. For comparison purposes, specimens from no-weld regions were also prepared in the same orientations and tested. The specimens with 45°-weld exhibited the lowest tensile strength, followed by the specimens with 90°-weld, no-weld and 0°-weld specimens. Comparison of failure strains and fracture modes revealed that weld regions are less ductile than the no-weld regions. Microscopic observations of fractured surfaces and further analysis revealed that Mg 2Si precipitates that align along the charge weld cause premature failure at these locations.

Publication Title

Journal of Materials Science

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