Computational modeling of a 3D matrix of duplex stainless steel and its ultimate strength in function of the sigma phase evolution

The appearance of intermetallic phases in steels is a matter of great interest due to the harmful character they can confer to the material's mechanical properties. This study presents the effect of the sigma phase's appearance for duplex stainless steel through numerical computational modeling. First, this work simulates a duplex microstructure matrix by a computational stochastic method. Subsequently, it uses this matrix to simulate the sigma phase's nucleation and growth. The Causal Cone method is the base of the nucleation and growth algorithm. The phase transformation code developed gave good results. The computational method calculates many parameters to evaluate microstructural development by stereological measurements. With the Linear Mixing Rule, the computational code predicts the material's mechanical properties. The study compares the data found in the literature against the numerical simulation outcomes. It was possible to verify the increase of the hardness for more significant volumetric fractions of sigma. The results present the transformed microstructure, the growth kinetic, and the mechanical properties evolution in time. This new technology saves money, time, sample, and human resources in carrying out a practical laboratory experiment.