Monte Carlo simulation of three-dimensional nonisothermal grain-microstructure evolution: application to LENS rapid fabrication

摘要

A stochastic three-dimensional(3-D)model for grain-microstructure evolution during transient non- isothermal annealing of metalic materials is developed, validated, and applied to the LENS(Laser- Engineering Net Shaping)advanced rapid fabrication process. The model is based on the assump- Tion that the main driving force for microstructure evolution is the reduction in energy contribution Arising from the grain boundaries. A temperature-dependent grain-boundary mobility factors is in- Troduced into the expression for the transition probability in order to account for nonisothermal ef- Fects, such as those induced by the rastering laser during LENS-based manufacturing.