Strain-Life Fatigue Testing of Additive Layer Manufactured Titanium Alloy TI-6AL-4V by Electron Beam Melting

摘要

Additive layer manufacturing (ALM) methods,also known as 3D printing, are developingrapidly in many industries to reduce weightand lead times. With an additional advantagein aerospace for significant reduction inmaterial buy-to-fly ratio. Aerospace OEMs andsuppliers are identifying appropriateapplications for ALM components andprogressing their use from developmentprototypes, into components qualified forservice on production aircraft.This paper describes strain-life fatigue testingof a titanium Ti-6Al-4V alloy, additive layermanufactured by electron beam powder bedfusion into cylinders, machined and polishedinto tensile and fatigue test specimens. Theseare manufactured in two conditions; “asbuilt”, and after a “standard heat treatment”.The standard heat treatment condition isfurther examined to assess their directionalfatigue properties, using specimensmanufactured with build directions vertical,horizontal and at 45 degrees to the axis of thespecimen.In conclusion, fatigue tests on additivemanufactured material, including bothmanufacturing process and any postmanufacturing treatment, is consideredessential because the fatigue performancecannot be inferred from the equivalentwrought material or from the static strengthof the manufactured material.