Combining Fractography with High-Energy x-Ray Diffraction to Study Fatigue Crack Growth in Ti-6Al-4V

摘要

Fatigue crack growth in Ti-6Al-4V has been explored through the combined use of high-energy x-ray diffraction (HEXD) analysis, electron backscatter diffraction analysis, and fractography to draw a connection between the driving forces and micromechanisms of fatigue crack growth. Samples were prepared from a forging with two configurations, viz. with the crack plane either perpendicular or parallel to the primary extension direction of the forging. Crack growth was examined in situ by mapping the lattice strain fields using HEXD for loading at R = 0.1 and R = 0.7. The crack growth as assessed by HEXD was contrasted with predictions of linear elastic fracture mechanics. The variation in the lattice strain field with crystallographic orientation was assessed.At the microscale, a clear correlation between the availability of c-axes along the loading direction and facet formation was found.