Elucidating the Impact of Processing Parameters of Additive Manufactured Materials Using Microscale Tensile Samples

Abstract

Additive manufacturing (AM) using laser-based powder bed fusion (PBF) techniques results in a highly unique processing of material with complex, location-dependent thermal histories. The resulting microstructure and mechanical properties are highly dependent on the associated AM processing parameters and part geometry. To understand the property variation related to varying thermal profiles, a novel microscale testing technique was used to derive mechanical properties allowing for location- and orientation-specific characterization of the material that otherwise is masked with standard macroscale testing methods. Microtensile specimens with a footprint of 1 mm × 3 mm and a gauge section of 250 μm × 250 μm were extracted from part geometries designed to impart various thermal histories. The effects of build direction, sample orientation, and AM processing parameters also were studied. The utility of small-scale testing enabled characterization of properties of thin structural walls not measurable with conventional samples. A link between sample strength and build geometry, such as angle and wall thickness, was observed. The results are crucial to accurately design the AM process and to provide insight into the local mechanical performance of AM components.