Multi-Modality 3D Visualization of Hard-Alpha in Titanium Billets Utilizing CT X-Ray and Ultrasonic Imaging

The objective of this research program is to develop a nondestructive visualization methodology to characterize hard alpha [1] in titanium billets. Hard alpha is a low density, hard, brittle, stabilized alpha-phase region (inclusion) with high nitrogen and oxygen content in a titanium alloy. Hard alpha is often voided and cracked. The methodology will provide the ability to characterize the shape, size, orientation and composition (voiding, cracking, nitrogen content) of the hard-alpha inclusion so that these characteristics can be used as key input data for a flaw deformation model. This deformation model, in turn, will be used to determine: (1) how hard-alpha becomes deformed during forging (2) the probability of detecting (POD) hard-alpha in the final, forged components (3) the effects of hard-alpha on the in-service life of forged aerospace components