A Short Review on Welding and Joining of High Entropy Alloys

Abstract

High entropy alloys are one of the most exciting developments conceived in the materials science field in the last years. These novel advanced engineering alloys exhibit a unique set of properties, which include, among others, good mechanical performance under severe conditions in a wide temperature range and high microstructural stability over long time periods. Owing to the remarkable properties of these alloys, they can become expedite solutions for multiple structural and functional applications. Nevertheless, like any other key engineering alloy, their capacity to be welded, and thus become a permanent feature of a component or structure, is a fundamental issue that needs to be addressed to further expand these alloys’ potential applications. In fact, welding of high entropy alloys has attracted some interest recently. Therefore, it is important to compile the available knowledge on the current state of the art on this topic in order to establish a starting point for the further development of these alloys. In this article, an effort is made to acquire a comprehensive knowledge on the overall progress on welding of different high entropy alloy systems through a systematic review of both fusion-based and solid-state welding techniques. From the current literature review, it can be perceived that welding of high entropy alloys is currently gaining more interest. Several high entropy alloy systems have already been successfully welded. However, most research works focus on the well-known CoCrFeMnNi. For this specific system, both fusion and solid-state welding have been used, with no significant degradation of the joints’ mechanical properties. Among the different welding techniques already employed, laser welding is predominant, potentially due to the small size of its heat source. Overall, welding of high entropy alloys is still in its infancy, though good perspectives are foreseen for the use of welded joints based on these materials in structural applications.

Re-Melting Behaviour and Wear Resistance of Vanadium Carbide Precipitating Cr27.5Co14Fe22Mo22Ni11.65V2.85 High Entropy Alloy

“…The welding of high entropy alloys becomes more and more important due to the increased development in the field of alloy designs. This is reflected in the increasing number of publications in this field [ 17 ]. One aspect that is considered in the welding related HEA research so far are the mechanical and microstructural properties of the welds.…”

Welding of high-entropy alloys and compositionally complex alloys—an overview

“…First summarized investigations can be found in refs. [31][32][33][34]. These studies, however, do not encompass the systematic investigation of the underlying welding metallurgy and its influence on the desired properties.…”

“…2 Welding processing, challenges, and perspectives of welded HEA joints For the last 5 years, a continuously increasing number of scientific studies was published that contain the terms "welding" and "high-entropy alloys" [31][32][33][34]. In these recent studies, welding of 3d-transition-metal HEAs/CCAs was primarily investigated.…”

Laser Oscillating Welding of TC31 High-Temperature Titanium Alloy

“…As an important part of laser manufacturing technology, laser welding is currently one of the most notable and most promising welding technologies. Due to its advantages of high quality, low 2 of 13 deformation, high precision, high efficiency and high speed, laser welding technology has become a key joining method for airplanes and automobiles-with improved safety and structural weight reduction, clean and efficient shipbuilding-and nuclear power plant construction [13,14]. It is an effective way to achieve the upgrading of traditional industrial structures and achieve energy saving and emission reduction.…”