The influence of thermal distribution on macro profile and dendrites morphology based on temperature field simulation of 6061 aluminum alloy laser welded joint
Ting Liu, Xiaohong Zhan, Yue Kang
Abstract
Temperature distribution has an important influence on grain morphology during laser welding process. In this investigation, a three-dimensional finite element model considering the effect of different laser welding parameters on heat distribution was established. Moreover, the macro profile and grain morphology in different regions of 6061 aluminum alloy laser welded joints were studied considering different welding heat input. It was found that the upper and bottom weld widths increase with the welding heat input. As the welding speed and laser power increase, the high temperature regions during welding process are elongated in the welding direction. Besides, the size of coarse equiaxed dendrites in the center of weld seam increase with welding heat input and cooling rate. The thermal field simulation results shows that the different temperature distribution and temperature gradient in different regions of weld seam have great effect on grain morphology. Besides, the temperature gradient is smallest in the center of molten pool, while biggest at the edge of molten pool.