Open hole surface integrity and its impact on fatigue performance of Al 2024-T3/Ti-6Al-4V stacks

This work studies the open hole surface integrity of Al 2024-T3/Ti-6Al-4V stacks, which have been subjected to different making methods, namely, conventional drilling and helical milling. The resulting hole-exit burr, roughness machined surface/sub-surface microstructures characterized impact on fatigue performance coupons has revealed. Results show that milling can effectively reduce burr formation at cause minimal sub-surface microstructural deformation, especially in Ti layer. Helical produced holes with greater roughness, interestingly, life doubled drilling.