3D Dynamic Simulation Analysis of Thermal-Mechanical Coupling during 7075 Aluminum Alloy Micro-droplet Deposition Manufacture

In aluminum alloy droplet deposition manufacture process, thermal warping, layering and hot cracking of formed 3D components are the most common defects, which have been found to be associated with the large temperature gradient and thermal stress concentration. To obtain insight into the common defects formation mechanism in metal micro-droplet deposition manufacture, a 3D transient finite element (FE) simulation model has been developed by the APDL(ANSYS) code and element birth-death technique. The distribution and variation of time-dependent temperature and thermal stress fields were predicted and the thermo-mechanical behaviors were analyzed in fabricating aluminum alloy 3D components. And then, a series of deposition experiments were conducted using 7075Al alloy droplets under the setting process parameters (same to the initial and boundary conditions). The results show that the experimental results basically agree with the simulation results of thermo-mechanical behaviors. The reliability and correctness of the simulation model were verified experimentally by the measured temperature field and the observation of thermal deformation and hot cracking of formed 3D component. The work provides a useful theoretical and experimental guide for optimizing metal droplets deposition manufacture.