Multi-Scale Mechanical Property Prediction for Laser Metal Deposition

Abstract

The Laser Metal Deposition (LMD) involves extremely complex multi-scale multi-physics and multiple thermal cycles issues, making it difficult to accurately predict the resultant mechanical properties of fabricated components from given process parameters. This research, by proposing a cladding stacking model that uses the structural evolution history of the heat-affected zone, predicts the overall structure of fabricated components, and establishes a process–structure–property multi-scale simulation framework based on this model, a general solution for the abovementioned difficulty. Based on the Hot Optimal Transportation Meshfree (HOTM) method, a platform ESCAAS is developed to simulate the meso-scale Ti-6Al-4V powder evolution process. Based on the Cellular Automaton (CA) method, the micro-scale grain structure in the molten pool is simulated. The macro-scale mechanical property of the fabricated component is calculated based on a polycrystalline Representative Volume Element (RVE) model and the homogenization technology. Experiments including LMD multilayer printings, metallographic observations, and static tension are designed to verify the accuracy of the model and simulations. The results are greatly consistent with the experimental data and the relative error of the final mechanical property prediction is within 5.18%. This work provides a basis for the quantitative analysis of the process–structure–property relationship and the optimization of process parameters.

Keywords

• additive manufacturing
• heat-affected zone
• multi-scale
• process simulation
• grain growth
• property prediction