Mechanical behaviour of 6082-T6 aluminium alloy welds

Abstract

In the utilisation of aluminium alloys for structural applications, one difficulty to be overcome is the reduction of mechanical properties of welded joints as compared to the parent material, consequent upon the weaker strength of the Weld Metal (WM) and the deterioration in the Heat Affected Zone (HAZ) due to welding thermal cycles.

In this paper the microstructure and mechanical characteristics of joints welded with Gas Metal Arc Welding (GMAW) procedure, made of plates of 6082-T6 alloy, are investigated. Experimental work included Vickers microhardness test, tensile test, fatigue rotating bending test, Charpy V impact test and Scanning Electron Microscopy (SEM) fractography.
Diagrams of fatigue stress - cycles for parent and welded material were compared. Static tensile tests showed minimum strength in the HAZ, while fatigue strength and fracture toughness have minimum value in the WM. Fracture toughness in terms of KIC, estimated by empirical relations, showed the lowest value in the melted zone.