248 Prakt. Met. Sonderband 38 (2006) 
2. EXPERIMENTAL L: 
Welding. AlMg3 butt-joints were produced at Fronius International GmbH by CMT, MIG 
and laser hybrid welding using 1.5mm thick AIMg3-sheets and AlSi5-filler of 1.2 mm 
diameter (Fig.1). Optimized parameters for each welding process were chosen (tab.1). 
Distortion was minimized by clamping the sheets during the welding process. 
Microstructure and Texture. For optical (OM) and scanning electron (SEM) microscopy, 
sample cross-sections were ground, polished and etched. Electron Backscattered 
Diffraction (EBSD) was used for quantitative grain size and texture analysis. Vickers 
microhardness (HVO0.1) tests were carried out on polished cross-sections using a step size 
of 0.25mm. For TEM studies, small disks (3mm diameter) were cut out, polished down to 
0.1mm thickness and then thinned with a double jet technique at 243K using a standard 
electrolyte (91% methanol and 9% HNO3). Mic 
but 
Table 1: Welding parameters optimized for the CMT, pulsed MIG and laser hybrid weld pro 
Weld Lo [kW The 
| OMT re I en the 
Laser hybrid on = 70 16 2.7 The 
vs: Welding speed in [cm/min], vp: Wire feeding speed in [m/min], I: Current in [A], U: Voltage in join 
[VI], Ly: Laser power in [kW] (Fig 
and 
Residual Stresses. Residual stress analysis was performed using the instrument G3 at (Fig 
HASYLAB at DESY, Hamburg, Germany at 6.4keV. Residual stresses in the longitudinal reve 
and the transversal weld direction were determined at the top of the butt-joints using the with 
siny method (Alz14 reflection). The diffraction elastic constants were calculated using the pari 
Kröner’s model [7]. Fig. 
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