Residual Stresses in Resistance Spot Welded AZ61 Mg Alloy

• The use of magnesium alloys has been rapidly increased due to their ability to maintain high strengths at light weights. However weldability of steels and aluminum alloys by using resistance spot weld (RSW) process is a major issue, because it cannot be directly utilized for magnesium alloys. In this study, a structural-thermal-electrical finite element (FE) model has been developed to predict the distribution of residual stresses in RSW AZ61 magnesium alloy. Thermophysical and thermomechanical properties of AZ61 magnesium alloy have been experimentally determined, and have been used in FE model to increase the accuracy of the model. X-ray diffraction (XRD) technique has been utilized to measure the residual stresses in welded samples, and its results have been used to validate the FE model. Comparison study shows that the results obtained by using FE model have a good agreement with the experimental XRD data. In specific, the results show that the maximum tensile residual stress occurs at the weld center while decreases towards the nugget edge. In addition, the effects of welding parameters such as electrical current, welding time, and electrode force have been investigated on the maximum tensile residual stress. The results show that the tensile residual stress in welded joints rises by increasing the electrical current; however, it declines by prolonging the welding time as well as increasing the electrode force.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Annan materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Other Materials Engineering (hsv//eng)

Nyckelord

Resistance spot weld

AZ61 mg alloy

residual stresses

finite element model

x-ray diffraction

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