Gravitational effects on the microstructural evolution of GTA welds in an Al-Cu alloy

Al-Cu 합금의 GTA 용접에서 중력에 따른 미세조직 거동에 관한 연구

Gas tungsten arc welds on Al-4 wt% Cu alloys were investigated to determine effects of gravitational orientation on the weld solidification behavior. Outward convection flows in the parallel-down weld might be inhibited because of its reverse direction with respect to the gravity vector. This resulted in abnormal 'S' shape of the trailing s-1 interface and the solidification rate (Vs), which was receded toward the weld pool center. Significant influence of gravitational orientation resulted in the variation on the weld pool shape associated with convection flows, which in turn affected solidification orientation/morphology and the primary dendrite spacing(λ$_1$).