Additive Manufacturing-Enabled Advanced Design and Process Strategies for Multi-Functional Lattice Structures

The properties of each lattice structure are a function of four basic lattice factors, namely the morphology of the unit cell, its tessellation, relative density, and the material properties. The recent advancements in additive manufacturing (AM) have facilitated the easy manipulation of these factors to obtain desired functionalities. This review attempts to expound on several such strategies to manipulate these lattice factors. Several design-based grading strategies, such as functional grading, with respect to size and density manipulation, multi-morphology, and spatial arrangement strategies, have been discussed and their link to the natural occurrences are highlighted. Furthermore, special emphasis is given to the recently designed tessellation strategies to deliver multi-functional lattice responses. Each tessellation on its own acts as a novel material, thereby tuning the required properties. The subsequent section explores various material processing techniques with respect to multi-material AM to achieve multi-functional properties. The sequential combination of multiple materials generates novel properties that a single material cannot achieve. The last section explores the scope for combining the design and process strategies to obtain unique lattice structures capable of catering to advanced requirements. In addition, the future role of artificial intelligence and machine learning in developing function-specific lattice properties is highlighted.