A cellular automata-based crystal plasticity analysis of slip activity in additive manufactured Ti-6Al-4V during dwell fatigue

A numerical approach combining cellular automaton and crystal plasticity finite element methods was proposed to investigate slip behaviors of additive manufactured Ti-6Al-4V material under dwell fatigue condition. Compared with conventional polygon-based microstructure models, the proposed method generates microstructures that more closely resemble the actual material and allows the simulation to explicitly account for the influence of grain shapes on local stress distributions and slip system activation. A Burgers orientation relationship based minimum elastic strain energy indicator was introduced to determine the α-variant selection during the β-to-α phase transformation. A cellular automata code, ExaCA tool was utilized to generate a selective laser melting fabricated microstructure. The crystal plasticity parameters of the model were calibrated based on tensile test results of the additive manufactured specimen and subsequently applied to the dwell fatigue simulation. The results reveal material hardening arising from accumulated slip system activations and show the relationship between load shedding and slip activity, which is consistent with our previous findings. This approach overcomes the limitations of traditional modeling methods and offers the potential to elucidate the underlying fatigue mechanisms of additively manufactured Ti-6Al-4V alloys. • A crystal plasticity model was developed with cellular automaton method. • Grain morphology evolution was considered in simulation. • A phase transformation method was proposed based on Burgers orientation relation. • Crystal plasticity parameters were calibrated against experimental results. • Dwell fatigue behavior was investigated by studying slip behaviors.