Computational heat affected zone microstructure simulation - Normal grain growth

The mechanical properties of a weldment are significantly influenced by its heat affected zone microstructure. An understanding of the latter is thus essential for realizing and predicting the mechanical properties of a weldment. However, traditional analysis of the micro structure involves metallographic examination, which is both destructive and time consuming. To enhance the capability for non-destructive and real time microstructural prediction, a dimensionalized Monte Carlo-based computer simulation technique has been developed to simulate the evolution of grain structure in the steep temperature gradient environment of the heat affected zone as arises during laser processing. Large matrices, consisting of 200 × 200 sites with 100 possible grain orientations, were used for the simulation to obtain a detailed evolution of the grain structure. Grain growth simulation in the heat affected zone of pure copper that is based on a point heat source thermal model has been generated using a matrix with random initial site orientations. The simulation results are analyzed for grain size distribution. Both the grain size distribution and the gram growth direction throughout the heat affected zone show reasonable agreement with existing experimental results.