Mechanical properties of lattice materials for fatigue-tolerant design and fabrication

Additive manufacturing techniques allow the structuring of components having complex geometries that cannot be realized through conventional manufacturing techniques. In the case of architected cellular or lattice structures, the control of the micro-architecture allows tailoring the component to achieve various characteristics both from the mechanical and other performances point of view, thus offering several advantages. Lightweight design, extended surfaces, and regularly arranged and interconnected pores constitute useful and increasingly required characteristic in medical, automotive, and aerospace fields. Regardless of these advantages, issues concerning their structural integrity, together with the complexity of the manufacturing process, limit their applications. Several potential manufacturing errors can occur; therefore the reported characteristics of these types of structures are not consistent. Specifically, poor fatigue properties are often reported. However, advancements in metal additive manufacturing processes have made it possible to understand the relationship between the additive manufacturing process and the mechanical properties of the fabricated parts using this process. Therefore additively manufactured cellular structures have promising applications in the industrial sector. This chapter examines the current knowledge regarding the fatigue properties of additively manufactured cellular structures. Important aspects regarding the design, fabrication, and mechanical characterization of such structures are discussed.