Numerical simulation of thermal processes in cold metal transfer-based additive manufacturing

Wire arc additive manufacturing (WAAM) based on cold metal transfer (CMT) technology is very suitable for additive manufacturing of light metals such as aluminum and magnesium alloys due to its low heat input. The temperature field in CMT additive manufacturing determines the microstructure evolution and mechanical properties. However, the mechanism of CMT-related process parameters affecting the thermal process and molten pool geometry in additive manufacturing is still unclear. The finite element analysis model of the CMT additive manufacturing process was established based on element birth and death technology, and the temperature field and molten pool shape in the CMT additive manufacturing process were quantitatively studied. The results show that with the increase in welding speed, the maximum temperature of the molten pool decreases, the length of the molten pool decreases, and the depth of the molten pool changes little. The effect of interlayer cooling on the temperature field of CMT additive manufacturing was quantitatively analyzed. The study found that without cooling between the deposited layers, heat accumulation will occur in the component of additive manufacturing, and the peak temperature will be higher. With the increase of the additive manufacturing layer number, the peak temperature of the additive manufacturing layer increases. With the increase of additive layer number and no cooling between sedimentary layers, the length of the molten pool increases obviously. The correctness of the model is verified by the experimental measurement of weld geometry in CMT additive manufacturing of AA5356 aluminum alloy. This study provides a theoretical basis for the optimization of the CMT additive manufacturing process of aluminum alloy.