The Status of High Entropy Alloys Studies in Africa: An Overview

Abstract

One valid way to access the state of knowledge in a specific research area is by assessing the availability of quality publications in that research area. In this work, we assess the level of high entropy research in Africa considering that it is a hot topic in the field of materials engineering. Precedent on the independent studies of Cantor and Yeh, the conventional alloying techniques are evolving towards the high entropy approach. To determine the extent of high entropy research in Africa, SCOPUS database was used following specific keywords searches. The result ranked South Africa as the most publisher of high entropy alloy-related articles in Africa followed by Egypt then Kenya, Nigeria and Algeria. Notably, most high entropy alloy articles published from South Africa and Egypt are within the last two years. In South Africa, the high entropy alloys are majorly fabricated via arc melting, spark plasma sintering and laser deposition techniques while Egypt shows proficiency in studies focusing on mechanical alloying, sintering and casting processes for high entropy alloys. Conclusively, the research output from Africa is still lagging when compared to those of other continents however, maximizing the limited infrastructure within Africa and improving collaborations will go a long way towards improving Africa’s research output on high entropy alloys.

Cold Spray Coatings of Complex Concentrated Alloys: Critical Assessment of Milestones, Challenges, and Opportunities

“…The field of CCAs is less than 30 years old and most of the alloy families show better structural and functional properties than dilute or conventional alloy systems [185,[298][299][300]. As coating material, the classes of CCAs fall under the broad category of 3D transition and refractory metals.…”

“…Approaches such as the ultrasonic atomization process are being explored but could be quite expensive and not easily scalable. Other factors hindering scalability have been highlighted [2,20,185].…”

“…These alloys extend the frontiers for alloy design beyond the conventional dilute alloying concentrations with potentially different properties for structural and functional applications [1][2][3]20,185]. The excellent structural and functional properties are attributed to four core effects.…”

“…The core effects and the relationship between the science and the physical metallurgy of CCAs are schematically shown in Figure 10. The entropy effect focuses on the thermodynamics; sluggish diffusion drives the kinetic phenomenon; severe lattice distor- These alloys extend the frontiers for alloy design beyond the conventional dilute alloying concentrations with potentially different properties for structural and functional applications [1][2][3]20,185]. The excellent structural and functional properties are attributed to four core effects.…”