## 3 Results and Discussion  
### Appearance and Mechanical Properties  
Figure 6 shows a cross-sectional image of a weld using each wire. All welds showed good shape without defects. Figure 7 shows the fracture location of the weld after the tensile test. As a result of observing the fracture location after the tensile test, the W1 and W2 welds with a tensile strength of 292 MPa, lower than the strength of the base metal, were fractured at the center of the weld metal. In contrast, the W3 weld, which had a tensile strength of 305 MPa, similar to that of the base metal, was fractured along the fusion line. Figure 5: Schematic design of the dilution rate measurement method of weld: (**a**) sum of deposited metal and molten metal; (**b**) molten metal. Figure 6: Cross-section of aluminum 5083 alloy gas metal arc welds using filler wires with different magnesium and manganese contents: (**a**) W1; (**b**) W2; (**c**) W3. Figure 7: Fracture appearance of aluminum 5083 alloy gas metal arc welds using filler wires with different magnesium and manganese contents: (**a**) W1; (**b**) W2; (**c**) W3. Figure 8 shows the tensile test results using the filler wires with different magnesium and manganese contents. In the case of the weld using W1 and W2, the average tensile strengths were 292 MPa and 293 MPa, respectively. An attempt was made to compare the strengths of the W1 and W2 welds to the difference in the magnesium content of the filler wire, but the tensile strengths of W1 weld and W2 weld did not show significant differences. However, the W3 weld showed an average tensile strength of 305 MPa, despite the lower magnesium content than the W1 weld, and its highest tensile strength was 310 MPa. In the results of Kwon [6], the magnesium concentration and strength of the filler wire were said to be linearly proportional, but the above experimental results showed non-linear results. The weld using commercial aluminum 5183 alloy wire had an average of 283 MPa and showed the lowest strength compared to the welds of the three types of manufactured wires, W1, W2, and W3. Figure 9 shows the appearance of the specimen after a bending test of each weld. All specimens showed good welding quality as the bending angle could reach up to 180\({}^{\circ}\) without defects, such as cracks on the weld surface. Figure 10 shows the hardness measured for each line of all welds. In the W1 weld, the hardness decreased by about 9 HV on average from the heat-affected zone to the deposited metal zone. In the W2 weld, the hardness decreased by about 14 HV on average from the heat-affected zone to the deposited metal zone, and, in particular, the hardness decreased relatively sharply in the deposited metal zone. In the W3 weld, the hardness of the heat-affected zone and the deposited metal zone was similar in line A and line B,  
Figure 8: Tensile strength of aluminum 5083 alloy gas metal arc welds using filler wires with different magnesium and manganese contents. Figure 9: Appearance of aluminum 5083 alloy GMA weld bending test specimen using filler wires with different magnesium and manganese contents: (**a**) W1; (**b**) W2; (**c**) W3. and the hardness was slightly decreased in line C (the second pass) due to high heat input. The maximum hardness of the W1 weld was similar to that of the W3 weld, but the minimum hardness was relatively low. At the same arc heat input, the magnesium vaporized, and the hardness decreased in the W1 weld, but, in W3 weld, the magnesium was also vaporized, but the manganese remained in the deposited metal zone without vaporizing, so the hardness value did not decrease and was relatively high. As a result, the W2 weld showed the lowest hardness value compared to the other welds. The difference between the maximum and minimum hardness at the W1 weld and the W2 weld was relatively more significant than the W3 weld due to the magnesium vaporization in the weld metal. In the W3 weld, the hardness did not decrease moderately, and the deviation was slight because the manganese remained without vaporization.