Microstructure design is key in targeting the desired material's properties. It is therefore essential to understand the relationship between the properties and the microstructure, as well as what is driving them via a specific process, while also considering nay additive techniques. The following five journals participate in this Topic: Coatings, Alloys, Crystals, Materials, and Metals. Contributions related to microstructure design and characterization are collected in this Topic, together with their relation to the mechanical, fatigue, wear, and corrosion resistance of different kinds of metals and alloys. The goal of this Topic is to present contributions related to the relationship between the microstructure and properties of metals and alloys for different applications, including aeronautical and aerospace applications. Different process routes are considered (thermo-mechanical routes and additive manufacturing) in this Topic. Welding is a mandatory issue in many applications; this is why contributions related to welding are also included in this Topic. The Topic includes 19 research papers, 1 communication, and 2 review papers. Among those, 11 papers were published in Metals, 8 papers in Materials, 2 in Crystals, and 1 in Coatings, covering several aspects concerning microstructure-properties relations in metals and alloys.