Effects of Anisotropy in Polycrystalline Ti-7Al Using Far-Field High Energy X-Ray Diffraction Microscopy

<div>On the grain scale, materials are inhomogeneous and anisotropic, and these non-uniformities are often the initiation sites for failure. However, most traditional models assume a homogeneous and isotropic material to predict performance and failure, so focus has begun to turn to micromechanical materials models. These models rely on experiments which supply three-dimensional, in situ, multi-scale data to make accurate predictions. Titanium alloys are commonly used in many biomedical and aerospace applications. However, the alpha-phase in this material is both thermally and mechanically anisotropic due to its</div><div>hexagonal closed packed structure. This anisotropy can lead to the development of significant internal stresses in polycrystals. Far-field high energy x-ray diffraction microscopy (ff-HEDM), a synchrotron-based in situ x-ray characterization technique, is employed to study the micromechanical evolution of Ti-7Al under thermal and cyclic loading. In turn, this data will be used for the validation of micromechanical models and eventually the prediction of materials failure.</div>