Strain Field Visualization During Fatigue Crack Growth in Microstructure Tailored LPBF Ti‐6Al‐4V

ABSTRACT In this work, a multilength‐scale investigation of the impact of two postbuild heat treatments on the fatigue crack growth behavior of laser powder bed fusion (LPBF) produced Ti‐6Al‐4V is presented. Specimen microstructures are characterized using electron backscatter diffraction (EBSD) analysis. Evolving strain fields are obtained with digital image correlation (DIC) captured across the micro‐ and mesoscales as a function of crack growth during constant stress intensity factor fatigue experiments. The two postbuild heat treatments studied are a one‐step annealing (OSA) and an oscillating sawtooth heat treatment (SHT). Microstructure data from EBSD and evolving strain fields from DIC data are aligned to obtain visualization and quantitative support for observed fatigue crack growth behavior. The experimental data contained in this work provide insights into the processes governing fatigue crack growth in heat‐treated LPBF Ti‐6Al‐4V.