The Fracture Behavior and Mechanical Properties of a Support Structure for Additive Manufacturing of Ti-6Al-4V

Abstract

In the laser powder bed fusion processes for metal additive manufacturing, a support structure is needed to fix the part to the base plate and to support overhanging regions. Currently the importance of support structure for a successful build process is often underestimated and some effects are not yet well understood. Therefore, this study investigates the fracture behavior and mechanical properties of thin additive manufactured struts using the titanium alloy Ti-6Al-4V and specific machine parameters for support structures. Tensile tests were performed for different strut diameters and the fracture surfaces were analyzed using a laser microscope and a scanning electron microscope. Additionally, the porosity was examined with micro-CT scans. The results were compared with a different set of parameters used for solid parts. The experiments revealed that struts produced with support parameters had no significantly lower tensile strength than the comparative parts. Despite that, some porosity and around two percent of defects on the fracture surface for parts using the solid parameter set have been found. Parts with support parameters show no porosity, even though the energy density is around 30% lower compared to the solid parameter set.

Numerical modelling of parts distortion and beam supports breakage during selective laser melting (SLM) additive manufacturing

“…Also, since the supports' scanning strategies and geometries are different from the parts, it is assumed that the support material properties might vary. Thus, some studies have been considering tensile testing supports of different geometries [15,16,51] to characterise their behaviour. However, there is still a lack of data that could help AM-engineers to design supports, and standard methods to test these structures repetitively are still required.…”

A Review of the Latest Developments in the Field of Additive Manufacturing Techniques for Nuclear Reactors

“…However, these parts currently only exist in the study form, which is far from the practical applications in engineering due to the strict criteria in nuclear reactors. The AM metals have the features of building direction, heterogeneities and defects of voids and micro-cracks [34][35][36], which can cause the propagation of cracks and branching which can actively reduce fatigue life tremendously [37][38][39]. A series of microstructures with different morphological and crystallographic features were generated to study the effects of the individual texture on the mechanical properties of the AM stainless steels, which showed that the highest load-bearing capacity of the material occurs when the macroscopic loading acts under an angle of 45…”

A Structured Approach to Reduce Design Iterations in Additive Manufacturing

“…The first dimension is represented by the defect types and the second dimension by the properties. For example, a reduced cross-section due to porosity has an influence on ultimate tensile strength (Weber et al, 2020b), elongation, Young's modulus and fatigue performance (Stef et al, 2018). Another example of the influence on mechanical properties is surface roughness.…”