Layer-by-layer additive manufacturing (AM) of metals can be used to fabricate complex geometry components that cannot be manufactured using traditional casting, forging, or machining methods. However, the processing that metals are exposed to in AM, namely rapid solidification followed by repeated thermal cycles with the addition of layers, results in unique microstructures that differ drastically from their wrought or annealed counterparts. Before AM can be adopted for use in structural, or load-bearing, applications, a fundamental understanding of the connections among processing, microstructure, and properties must be developed. I will present our work on elucidating those links in monolithic components made by additive manufacturing. In addition, I will discuss our work in designing and characterizing functionally graded materials made by AM. In these materials, the chemistry is intentionally varied with position, with the aim of spatially tailoring properties (e.g., mechanical, thermal, magnetic) within a single, complex shaped, 3D component.