Optimized Phased Array Hard Alpha Inclusion Detection in Castings

"Current manufacturing technology for cast titanium components cannot guarantee theabsence of hard alpha inclusions.Under the effect of fatigue, such inclusions become likely sites for structuralfailure. By performing nondestructive inspections on the manufactured parts usingphased array ultrasound, one can eliminate parts with the largest inclusions.Despite such quality control, undetected inclusions can be large enough to decreasethe life expectancy of the parts by a factor of 20. To avoid such consequences,structural members can be made thicker but the added weight can decrease aircraftperformance. Even a 50% reduction in the size of the smallest detectable inclusionwould have significant life and/or weight benefits. Fortunately, the current phasedarray implementation has not been optimized. We therefore propose to optimally design a phased array for casttitanium inspection. We will explore reductions in beam diameter, changes in thenumber, size and arrangement of the elements, variations in frequency, and a varietyof imaging techniques to improve detection while reducing grain noise. Along withreducing the size of detectable inclusions, we will explore techniques to allow phased arrays to adapt to the complex part geometries of titanium castings. By reducing the size of the smallest detectable inclusion in cast titaniumcomponents, the U.S. Air Force will benefit financially through an extension of theinitial life span of new aircr