A dieless Nakajima test for additively deposited materials

Abstract. This paper focuses on a novel Nakajima test for characterizing the formability of additively deposited materials without extracting sheet blanks. Material is deposited by wire-arc additive manufacturing in the form of ‘Π-shaped’ vertical walls, and the testing regions are then machined to the desired thickness and shapes for subsequent deformation with a hemispherical punch in a press. Digital image correlation is used to obtain the strain loading paths of the deposited material up to failure. The novel test eliminates the need for the special-purpose tool setup of conventional Nakajima tests, simplifying the overall procedure and reducing costs.