*Editorial* **Impact Welding of Materials**

#### **Ivan Galvão 1,2,\*, Altino Loureiro 1 and Ricardo Mendes 3**


Received: 10 December 2020; Accepted: 12 December 2020; Published: 14 December 2020

## **1. Introduction and Scope**

Recent industrial criteria, focused on obtaining increasingly e fficient structures, require the production of multimaterial components. However, the manufacturing requirements of these components are not met by conventional welding techniques. Alternative solid-state technologies, such as friction or impact-based processes, must be considered. Impact welding processes have the advantage of presenting a very short cycle time, which minimises the interaction of the materials under high temperature. This fact strongly contributes to reducing the formation of brittle intermetallic compounds (IMCs), i.e., one of the main concerns of welding dissimilar materials. Moreover, as the influence of the welding process is confined to a very narrow band around the materials interface, similar and dissimilar welds with high-strength bonding and a minimal heat-a ffected zone can be produced.

The impact welding family encompasses di fferent welding processes, such as explosion welding, magnetic pulse welding, vaporising foil actuator welding, and laser impact welding. Although these processes share the main operating principle, consisting of a high-velocity collision between a flyer and a target, they di ffer in the way the flyer is accelerated. These processes also present very di fferent length scales, providing the impact welding family with a broad applicability range. The technical interest of impact welding is driving the ongoing development of many scientific studies, which are essential to optimise the current manufacturing processes by developing new welding strategies and solutions. The present special issue presents a sample of the cutting-edge research that is being conducted on the multidisciplinary field of impact welding.
