Measuring Residual Stress in Additive Manufactured Ti-6Al-4V with Synchrotron X-ray Diffraction

Synchrotron X-ray diffraction has developed into a powerful tool capable of measuring residual elastic strain (for computing residual stress) in application sized parts of varying geometries. Developments at the Cornell High Energy Synchrotron Source (CHESS), as part of the Air Force Research Laboratory led Materials Solutions Network at CHESS (MSN-C), have prioritized the development of capabilities transitioning X-ray measurement techniques into tools which are readily applied to materials and manufacturing problems. Critically, the program has focused on the ability to measure real parts with complex geometries. This talk will present residual elastic strain measurements of multiple additive manufacturing (AM) builds, including an AM build shaped to resemble an airfoil geometry. The curved geometry of an airfoil presents additional complication for data point generation and sample alignment, which are overcome by laser mapping the surfaces of the sample and smoothing with a finite element based workflow. In addition, we will discuss the data processing workflow with a focus on challenges particular to AM materials, including: data interpretation, measurement uncertainty and reference lattice parameter determination.