Technical Paper: Strain-life fatigue testing of additive layer manufactured titanium alloy Ti-6Al-4V by electron beam powder bed fusion

摘要

Additive layer manufacturing (ALM) methods, also known as 3D printing, are developing rapidly in many industries to reduce weight and lead times. With an additional advantage in aerospace for significant reduction in material buy-to-fly ratio. Aerospace OEMs and suppliers are identifying appropriate applications for ALM components and progressing their use from development prototypes, into components qualified for service on production aircraft. This paper describes strain-life fatigue testing of a titanium Ti-6AI-4V alloy, additive layer manufactured by electron beam powder bed fusion into cylinders, machined and polished into tensile and fatigue test specimens. These are manufactured in two conditions; "as built", and after a "standard heat treatment". The standard heat treatment condition is further examined to assess their directional fatigue properties, using specimens manufactured with build directions vertical, horizontal and at 45 degrees to the axis of the specimen. In conclusion, fatigue tests on additive manufactured material, including both manufacturing process and any post manufacturing treatment, is considered essential because the fatigue performance cannot be inferred from the equivalent wrought material or from the static strength of the manufactured material.