Investigating hole making performance of Al 2024-T3/Ti-6Al-4V alloy stacks: A comparative study of conventional drilling, peck drilling and helical milling

Abstract This work reports a comparative study on different hole making methods, namely conventional drilling, peck drilling and helical milling, for Al 2024-T3/Ti-6Al-4V stacks in aircraft applications. The impacts of methods with constant or varied machining parameters across the stacked structures have been investigated. resulting exit burr, surface roughness/microstructural change fatigue behaviour machined characterized detail. Results show that burr formation is most severe least produced milling coupons. Deploying varying (i.e. optimal each individual metal layer) can effectively reduce drilling. 3D morphology shows 2024-T3 contains multiple scratches trenches, while Ti-6Al-4V features regular feed marks. Helical leads to highest roughness, which be attributed abrasion caused by evacuated chips. Sub-surface microstructural analysis layer more prone machining-induced white and/or grain plastic deformation along direction). relatively low performance related presence brittle these eliminate improve life 72% 38%, respectively. longest stack (~ 100% 40% greater than respectively).