PSI - Issue 13

Yanning Guo et al. / Procedia Structural Integrity 13 (2018) 806–812 Yanning Guo/ StructuralIntegrity Procedia 00 (2018) 000 – 000

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Effects of different welding rotation speeds on the flow stress and the ductility for 2024 stirred zone is shown in Fig.3. The flow stress and fracture strain of five tensile tests are quite different. Under the rotation speed of 400rmp, heat affected zone (Sample 1 and Sample 5) and stirred zone (Sample 3) show much better tensile ductility, about 25% higher than that of samples welded with the 600rmp rotation speed. However, for the thermo-mechanically affected zone (Sample 2 and Sample 4), the flow stress of 400rmp is about 12% higher than that of 600rmp. Therefore, the rotation speed has a significant influence on welding joint mechanical properties. Under the same welding speed, the higher rotation speed generates higher welding temperature on the joints, which leads to more refined grains and shows the higher strength of extension and ductility to the stirred zone.

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Fig.3 Comparison of 2024 stress-strain curves with different rotation speed (1300 s -1 ): (a) Sample 1; (b) Sample 2; (c) Sample 3; (d) Sample 4; (e) Sample 5